If you haven't already, make sure to check out the original UYP series on YouTube and PeakHD.net.
When we're dealing with powerbuilding, it's often helpful to start with the microcycle and work our way up, rather than the other way around. (Remember: your microcycle is usually your training split.) That's because no one competes in powerbuilding — you'll have to pick one at some point — and so it's more or less restricted to offseason training.
So, when we start out, we're dealing with pure beginners. Regardless of a size or strength goal, it's usually best to begin with high frequency and lower volumes and intensities, as you need little stimulus to grow, and we want to maximize the number of growing opportunities. So, that means full-body.
Eventually, you'll get too strong for a full-body workout to be practical, in terms of time or recovery requirements. At that point, it's usual to move to an upper/lower split. That way, we can get in more volume per session (and therefore more stimulus) because we're tackling fewer body parts or movements in each one. The tradeoff, of course, is reduced frequency.
It's the same when you finally move to a push/pull/legs or squat/bench/deadlift setup. That whole evolution of building strength and work capacity and changing your microcycle to match should take 2-5 years, depending on the individual.
Up until this point, the vast majority of powerlifting and bodybuilding programs could be considered "powerbuilding," as they'll largely focus on the squat, bench, and deadlift, (and maybe OHP), with more or less assistance work depending on the goal.
Once you've hit a plateau with that progression, things get more complicated. This is usually the beginning of the "information seeking" phase, which is probably why you're here — so we'll tackle that in the next episode.