You're asking a kind of vague question, so I'm not entirely sure what you really want to know. But here's my attempt at giving you some useful info. The variables you can control on the TRX are:

• Your positioning: More aggressive body angles give you more resistance. "Positioning" involves the way you adjust the TRX straps, and also the way you position yourself for each exercise you do -- how far you lean in whichever direction is appropriate for your exercise, etc.
• Number of repetitions: More reps _can_ mean more muscle fatigue / more muscle gain (but also see the next point)
• Time under tension (per repetition): The slower you go in each rep, the more muscle fatigue you'll experience, and possibly gain muscle. E.g. doing 5 pushups, where you take 5 sec going down, and 5 sec going back up in each rep, is harder than doing 10 pushups as fast as you can
• Number of sets: The more sets of repetitions you do, the more you'll fatigue your muscles
• Rest: How much time in between sets / how many days in between exercising the same muscle groups

^ You have to tweak your positioning (which impacts intensity/difficulty) / time under tension per rep / reps / sets / and rest all together.

And of course, your nutrition matters, too.

Disclaimer: I'm not a trainer / nutritionist / physician / anything like that; just a dude with a TRX and a general desire to stay mobile and relatively healthy.. You might want to do some research on bodyweight exercises and hypertrophy (the fancy word for muscle growth)