I don't know if it's so much myth as it is disinformation. Working out to gain whatever the personal goal may be need not be overly complicated but a lot of people tend to make it that way. A lot of success depends on a little study of how the body functions to a new or unaccustomed stress level/load and how the body can adapt and improves by becoming stronger. So it's pretty much stress, recovery and advancement to be ready for the next workout, for physical gains. The interesting thing is is that not everyone respones to exercise the same way. Any serious lifter will follow his/her own personal quest to see how the body respones to different sets, reps, length of workouts, day's a week, etc. That's when experience and logic come into play together to find what may work for you. If no noticable results in 3-4 weeks than choose another style of working out. But to be fair, give a program at least a 3 week, with serious intent, investment. All people don't respone at the same speed, as suggested above.
I might suggest starting from the point of the lowest common denominator when starting a workout program. One or two sets an exercise with the rep range between 8-12, basic 2 or 3 times a week. Food is a healer and a builder of the body. Too many guy's rush in to buy supplements they really don't need when first getting serious about BB'ing....Mistake. Do a little research about diet and foods, consider what you may need or adjust in your daily eating habits. The mean average is 3,000 calories (US male) for body maintence . Use that as a general gage as to how many calories you may need for lifting goals: muscle mass, fat loss, etc.
There is a motto on our gym wall, K.I.S.S. (Keep It Simple Stupid). No matter what some may have you believe, training is not brain surgery. It does not have to be complex or confusing. Good Luck.