Your best bet is something like this: https://animeartacademy.com/courses/187489/lectures/2850676
It's genuine advice, its extremely basic, and its literally tailor made for creating this kind of anime drawing.
The most important lessons are using atari lines for balance, and getting your proportions right.
Knowing a few stylized features like eyes, etc.
And what is not covered here but is very important is a little bit of perspective. Animation level perspective is fine: overlap, far things on a different surface and smaller than close things, contour lines, and foreshortening (close things are farther apart, far things are closer together). I'd actually draw you an example but I'm sick right now and my neck is killing me. Sorry bout that.
What others have said is also true. You can use really simple shapes like ovals and boxes, just to get your proportions and positioning right at first, then you can refine them with more detail. It doesn't even matter if they're in perspective or flat 2D if all you want is to practice copying as a super beginner lesson.