All you've got to do is go to one of these websites and follow the disassembly/assembly instructions. The text and photos will teach you everything you need to know.
Here! I wrote this years ago for someone else. You're welcome to use it if you like:
To answer your question, ‘PTOOMA’ is an acronym. Loosely, it stands for, ‘Pulled This Out Of My Butt’.
SLIDE ASSEMBLY TAKEDOWN -
(1) Should begin with removal of the magazine – Full removal, and storage away from the work area.
(2) Then lock the slide back for, both, visual and tactile verification that the chamber is empty.
(3) Lower the slide; point the pistol in a safe direction, and pull the trigger.
(4) Slightly withdraw the slide and pull down on the slide lock. Ease the slide and barrel assembly forward until it’s off the frame.
(5) Remove the recoil guide rod and spring.
(6) Remove the barrel.
(7) Use the flat side of a small screwdriver's blade to push back on the edge of the firing pin spacer sleeve. This releases pressure on the rear slide cover.
(8) SLOWLY remove the slide cover while keeping your thumb on top of the opening in order to catch that (mischievous) spring loaded bearing that often tries to pop out and get lost on the floor.
(9) Remember that the extractor depressor plunger rod has the spring at the rear of the slide. (You’ll need to know this when it’s time to reassemble!)
(10) Once the extractor depressor plunger rod is removed, the firing pin safety and the extractor will fall out. (Give the FP safety a push to get it to let go of the extractor.) At the same time be careful not to lose that little spring that sits on top of the firing pin safety.
(11) Draw down on the firing pin spring and remove the spring cups. (It’s a good idea to keep a small container on your workbench to hold small parts like the FP safety spring, extractor depressor plunger spring, and spring cups.)
That’s it! The slide assembly has, now, been successfully taken apart.
FRAME ASSEMBLY TAKEDOWN -
(1) On most (but not all) Glocks you’ve got 3 pins to deal with. The number one pin is the, ‘Lock Block Pin’. It is the highest pin and sits above the number two, ‘Trigger Pin’. The number three pin is the, ‘Trigger Housing Pin’.
Just so you know, the number one and two pins should always be removed in the precise sequence of number one, first, followed by number two.
NOTE #1-1: Glock has recently changed the recommended order for removal of their frame pins; however, Glock pistols are NOT target rifles; a Glock's frame pins are NOT high quality action screws; and I do NOT buy the factory's rationale behind this peculiar change to - I think - absurd technical advice. As far as I'm concerned the recommended removal and installation pin process should remain: 1, 2, 3; and this is how I continue to do it.)
NOTE #1-2: It does not matter when or how you remove the number three pin. You can do this with or without removing the number one and two pins. The important thing to remember is that whenever you intend to remove all three pins, they should be removed, together, in the precise order: one, two, three.
NOTE #1-3: The Glock armorer’s tool (or any long shank 3/32" punch) is all you need to remove a Glock’s pins. Excessive force is not needed. DO NOT USE A HAMMER! If the number two pin hangs up, first make certain that the slide stop, itself, is set squarely on the pin; if it is, then, simply wiggle the slide stop up and down until it lets go.
(2) Generally, use AR15 maintenance protocol for removing the pins from a Glock: From the left side of the frame to the right side of the frame. If a pin hangs, try inserting or removing it in the reverse direction.
Guide the tip of the punch with the thumb and index finger of your support hand. This will prevent the punch from slipping and marring the frame.
(3) With all the pins out, remove the lock block by prying upward at the back of the block with either the armorer’s tool or the blade of a small screwdriver. Then remove the trigger bar and trigger housing unit as a complete assembly.
(4) Hold the complete trigger assembly in front of you with the trigger on your right-hand side, and the trigger housing unit on your left. Pull slightly forward and toward the right on the trigger bar. Now, while holding the trigger housing unit perfectly still, move the trigger bar inward, toward your body, at about a 15 degree angle.
The combination of this slight angle and the forward stretch on the trigger (return) spring will cause the trigger bar to disengage from the trigger housing unit.
(5) Remove the trigger (return) spring and separate the trigger bar from the housing unit.
IMPORTANT: Notice that the trigger (return) spring is installed in the exact shape of the letter, ‘S’. On reassembly do NOT install it as a reversed (backward) ‘Z’.
(6) On third generation Glocks: Now turn the trigger housing unit over to the side opposite the connector. You’ll see a small hole directly behind the bottom of the connector bar. Insert the 3/32’s punch through this hole and push the connector out of the trigger housing unit.
(7) Critical Component Check!
The one part that holds everything else together on a Glock is not what you might think: It’s NOT the slide lock, and it’s not the lock block! Instead it’s that little leaf spring that sits in the frame, just forward of the lock block, and underneath the slide lock, itself.
NOTE 7-1: The slide lock spring is the one part that actually holds the slide and frame together! Like extra spring cups, this is that other Glock part that every field expedient repair kit should contain.
The slide lock spring should be periodically examined against incipient failure.
(8) In order to examine the slide lock spring, press down on it from above. This releases pressure on the slide lock which may then be removed by simply letting it fall out to one side or the other. Now lift up on the top of the slide lock spring and remove it for cleaning and examination.
(9) Whenever you reinstall the slide lock into the frame always make certain that the, 'U' shaped flange on one side of the slide lock is facing to the pistol's rear.
(10) Optional: Personally, I have never found a good reason to remove the magazine catch; and, the factory recommends that you should generally leave it alone. If, however, you want to change or remove this part, then, simply push the bar spring to the right and pull it out of it’s recess by moving it through the frame cut. It goes back in the same way. The magazine catch may, now, be removed from the frame.
That’s it! The frame has, now, been successfully taken apart.
REASSEMBLY SNAFUS -
(1) As previously mentioned: Don’t install the trigger (return) spring backwards!
(2) Simply reverse the disassembly directions to reattach the trigger bar and trigger housing unit. The connector goes on BEFORE the trigger bar is attached.
(3) You can use the back of the slide as a mandrel in order to compress the FP spring and hold it in place while reinstalling the spring cups. Place the striker (FP) assembly backwards into the proper slide channel, and catch the lip of the FP stud on the back of the slide in order to compress the spring.
NOTE 3-1: Do NOT allow the very end of the striker (FP) spring to line up with either side of the seam between the spring cups.
(4) Assemble the extractor and FP safety in their respective positions BEFORE fully inserting both the striker (FP), and the extractor/depressor/plunger rod.
NOTE 4-1: Now is the proper time to check your striker (FP) for proper performance by trying to push the firing pin all the way forward with the striker (FP) safety in both the up, and down positions. (Read the Owner's Manual for more details.)
(5) The frame pins are replaced in the exact order: one, two, three - Generally by working from the right side of the frame to the left. The leaf spring on the slide stop must be placed UNDERNEATH the number one pin. If the number two pin hangs up, simply wiggle the slide stop up and down until it catches the groove.
Use the top of THE HANDLE of the armorer’s tool in order to insert the frame pins most of the way into their respective holes. Then, guide the shaft of the armorer’s tool with the tip of your working thumb as you seat each pin.
(6) There is a flange on the slide lock. That right angle flange must always point toward THE BACK of the frame – away from the muzzle. (Smooth side forward)
(7) Do NOT insert any magazine into the frame until after you have completely function checked the pistol.
As a matter of fact, it’s a very good idea NOT to keep any loaded magazine or ammunition in the vicinity of your workbench.
Instead it’s better to have to get up and walk away from your work area in order to locate any magazine, or any ammunition, and thereafter load the pistol. Gun repairs and cleaning are best conducted away from any and all access to ammunition.
(8) If you want to check the slide stop for proper function, use an empty magazine and do it as the final step in the reassembly process - BEFORE moving on to actually loading the pistol with live ammunition.
(9) Finally, anytime you remove a Glock’s slide from the frame, the first thing you should do BEFORE reconnecting the slide and frame, back together, is to push down with your thumb on top of the larger end of the guide rod in order to make sure that the guide rod is fully seated in the assembly groove. This will prevent jamming the slide and frame together and, possibly, locking the pistol up while you try to figure out what’s not working.
FINAL NOTE: I am NOT a Certified Glock Armorer! (I'm only the armorer that Gaston Glock has forced me to become.) If I’ve made any mistakes, here, I’m more than certain that I’ll hear about it, shortly!