At the beginning just eat eat eat. Ty to get 2g of protein for every kg bodyweight. Additionally you can buy Whey-Protein and use ~30g after every Training

Just dont even think about steroids until you didnt train at least 3-5 years intense.

For the beginning 3x 90-120min are more than enought. Try to train your whole Body, also your Legs. Dont do too much on machines, and more with free weight and look for a good technique at exercises like squats, benchpress, militarypress, deadlifts and all the others. Dont do too much weight, clean technique is better and start with every exercise 3 sets of 12 repeats

Sorry for my bad english and wish you a good start ;)