Keep it simple and match your training to you and your body type and forget what everybody else is doing. By that I mean don't look at what your mates are doing in the gym or how much they can lift, everybody is different. For example dont fall into the trap of trying to follow Mr Olympias training method, its totally unrealistic to expect to get the same results as a guy who not only is likely genetically predisposed to building muscle mass but one who is certainly using ( abusing) steroids, growth hormone, insulin, etc, and spends more than the average person earns in a month on nutritional suppliments. So forget buying flex magazine LOL
Eat a balanced diet and if possible up you caloric intake slightly to allow your body to increase mass, starving wont make you get big. When you train match it to your body type. If you are Ectomophic ( small build, skinny) then train for just short intense periods, doing only a few sets ( 3 to 5) of each exercise using heavy weights ( ie keep the rep range between 15 max and 3 minimum as you increase the weights). Effectively you want to be training like a powerlifter.
If you lean more towards Endomorphic ( large build with tendancy to carry fat) then training should be longer to help burn fat and the rep count perhaps slightly higher 20 max and 5 minimum as you increase the weights. Maybe do 4 to 7 sets per exercise. No good building muscle if nobody can see it afterall.
Those naturally atheletic individuals, Mesomorphic ( naturally muscular and lean) would train somewhere in the middle of those above as a guide.
Pick 2 or 3 basic exercises at first for each major muscle group, stick to mass building movements like Squats, deadlifts and bench presses which will increase release of natural testosterone. Train the body fully on a cycle that will allow you recover again before retraining that bodypart again, so day 1 do Back and Biceps, day 2 Legs and Calves and day 3 Chest and Triceps. Rest on day 4 and restart the cycle on day 5, or you can have day 3 as your rest day then train Chest and triceps on day 4, followed by back and biceps on day 5, and have day 6 as your rest day, then legs and calves on day 7, and repeat that way, always having a rest day after 2 days training. do not underestimate how important recovery time is, this is when you actually grow, overtraining will actually reduce muscle growth......more is not better.
Just keep everything simple and the results will come, even those hard gainers with little genetic potential will still build up a body better than the average guy. Hope that helps