If you're way out of shape, you may have to do some training to get to the fitness level to do the kind of training you want to do.
On the other hand, you're only 26, so you're probably not in as bad shape as you think.
You should start with general core exercises, moderate weightlifting, and a variety of cardio. Look up periodization on the internet, you want to vary your workouts, build the intensity and duration over time, make sure you have rest days.
Exercise is stress, it damages your body and makes you weaker. REST between exercise is where your body repairs the damage, and makes it a little stronger to be able to handle that workload better next time. Work out too much, not enough rest, you end up losing ground, getting injured, or both. Not enough stress/exercise, and you don't do enough damage to your body to trigger it to rebuild stronger. Alternate a hard workout with an easier one, make sure you take at least 1 day off a week to rest.
As far as dieting goes, eat lots of small meals throughout the day. Drink lots of water. Eat healthy stuff, cut out the pop, the candy, the junk.
Do NOT start out with high intensity explosive/pliometric movements if you haven't worked out lately. Start with moderate weights, and get a month or two in at least before you start lifting really heavy. After you've built up your strength, you can start thinking about pliometric stuff.
Similar setup for cardio. You want to build up your base fitness before you can crank up the intensity/duration. After a couple months you can start to crank it up, doing interval training.
Periodization is the key to keep progressing and avoiding plateaus. A constant workout can be gotten used to. Changing it up a lot keeps your body challenged.
Rest is your friend. Cool down after workouts. Warm up good. Stretch when warmed up.
Keep it up, try for a routine and a diet that you can maintain over the long haul. People diet, lose the weight, can't wait to get off the diet and back to their old food habits, and gain the weight back. You want to stay healthy, long term, you need a healthy diet that you can stay on, not a short term thing that drives you to go right back to your old habits when you've reached your goal weight.