lol the answer, like a lot of things in life... is simple, but not easy. how to build muscle:
- nutrition. eat enough protein and calories. i don't think people have to overthink this. if you're getting fat and don't like what you see eat less. if you're constantly weak and tired eat more. if you're good at tracking cals/weight then do that.
- get enough sleep.
- pick a good beginners lifting plan: something like stronglifts or starting strength. these are help you build solid habits and good form, but in the end it's just picking up heavy stuff and putting it down until your muscles fatigue within a certain amount of reps. repeat the next week.
- the most important factor: consistency. even 2 good spaced out workouts a week will do wonders, but you'd be surprised how many people can't manage that. a shitty program and diet/sleep will be overcome by just straight consistency. you will progress slower, have an off week or two or three, but by the end of each year you will have progressed. this is where i think people fail the hardest, and think of it as some like grueling journey to the "finish line" as fast as possible when it's really a long marathon for the rest of your life. nobody wins an award for getting leaned out in 3 months vs 6, you're building habits for life (sorry, just a rant)
i'm obviously simplifying, but for most of the population and even for the "goal" pics in that article, you could train indefinitely on a basic program and achieve that.
having jumped on this train at age 29 and going on year 5, i can tell you that it all these tricks and tips might help you in the short term, but in the end everyone is going to learn some things the hard way and make some of the same mistakes over and over. there are no shortcuts (edit: unless you use some "help").