My advice, take or leave it, is to check out the Workouts subforum
and choose either the M&B Full Body program, or something close to it (full body, mostly big compound lifts).
Like others have said more or less, lifting and eating (and water - drink lots of water!) are more important than any supplements, in general. But you can't go too far wrong with some basic whey protein (concentrate or isolate, whichever) every day, and cheap creatine (pure CMH would be fine) if you want to see how that goes. Other things you could consider, but that might not be essential, are fish oil, and Vitamin D3. Case by case, raelly.
Focus on eating plenty of protein-rich food, like meat, eggs, fish, dairy, stuff like that. And make sure you also get enough micronutrients (etc.), so eat lots of (different) vegetables, and some fruit too if you like.
If you want to count calories, then do so, keeping in mind you'll want to be at a caloric surplus every day, to support the lifting you'll be doing.
As far as lifting goes, start LIGHT, leave your ego at the door, and progress *in some way* every session
. Could be reps, could be weight, might be both even. But the key is progression