Well, the first thing I would personally look at is where you stand in regards to body fat. If you have some fat you could lose, I'd hit that first by cutting calories and getting your body fat percentage in the 15% range. You can do this through diet alone, but a combination of diet and cardio isn't a bad option.
In regards to bulking, again start with your diet and learn what your BMR is and how many calories you need. Look at HIIT (High Intensity Interval Training) for bulking and combine that with appropriate balanced food intake (protein is a big part of this - check out bodybuilding diets, but remember that you'll need to adjust these to your calorie needs).
As far as particular exercises, I would recommend a focus on your shoulders (lat and side raises, shoulder presses), triceps (kickbacks, presses), traps (shrugs and scapular retractions), lats (isolated rows, pulldowns, pullups), chest (good old benchpress) and obliques (sideplanks, twists, cable crunches, etc.). Don't neglect your legs, though - you don't have to go crazy with them, but putting a bit of definition in your legs will help your overall "buff" look.
Don't expect overnight results. A lot of guys get discouraged working out because they think that being on T will somehow give them immediate results. Look at 5 to 6 months as a goal and if you get gains sooner, good for you.
If you want to bulk, be careful supplementing cardio because you don't want to lose your gains. If you must, I'd reduce cardio (once you start trying to bulk) to one day a week. You can use cardio in between your sets, though - for instance, if you're doing 3 sets - in the 90 second rest between sets, hit the treadmill or stationary bike.
As for how often, you'll hear all kinds of feedback from what works best for individuals. I'd start out with 3 days a week - keeping your workouts to about 45 minutes (no more than an hour) with about 3 sets of 8 reps each exercise. If you want, you could even do one day for shoulders, one day for arms, one day for back, one day for legs, etc. But each day, keep those sessions under an hour and remember to use less reps with more weight.
I would recommend waiting at least 3 months post-op before you hit the weights seriously.
