I'm doing 5x5 Program right now. My buddies have tried it and all vouched for how good it is. Helps your increase strength.
StrongLifts 5x5: Ultimate Strength & Muscle Building Program StrongLifts
My current workout program: Stronglifts 5×5 Beginner | My Journey to Godliness!
30minutes isnt enough time btw.. I think my warm up is about 10-15mins.. overall my average work out time is about 1hr 15mins.
My starting weight was 118lb (5"7) about year an a bit ago. Currently 145lb. Just know this takes time and consistency is KEY.
Even if you don't try the 5x5 program. Just remember to at least have these main exercises.
Squats, Bench (or Dumbbell press), Deadlifts, Shoulder Press
Ask people at the gym for help. Form is key, always stretch, and rest properly! I overworked my shoulder a while back and wasn't able to left my arm over my head for a solid month. Shit sucks. Lost progress and momentum.
Good luck buddy!
Oh right, remember to concentrate on the muscle & SQUEEZE!