>>2258453Dude there are like a million resources out there to get you started.
Start with big ideas, and get smaller. Knowledge wise, first learn the total proportions of the body. A body is 7 to 8 heads tall depending on build. A a head is generally a perfect circle, plus 1/3 of itself for the jaw. The shoulders are generally 2 heads wide. The hips are basically the same as the shoulder with variation dependent on build/sex. So on and so forth. You can learn and memorize the fundamental proportions of the human body easily in an afternoon. They aren't terribly complicated.
As far as actual execution, start with gesture and/or skeletal [stick figure] construction from life or references.
Artists that can draw without preparation and under-sketches can do it only because they've put in the time with their fundamentals. If you watched a guy play guitar and thought "man, he doesn't even have to look at a chord book or anything. I suck." Well you'd look pretty goddamn stupid. He obviously learned chords somehow. And so when starting out, use all the tools at your disposal and in time you'll be able to leave some behind just like the guitarist can eventually leave the chord book behind.