Drawing on the 3DS is hard in general, lol.
The way I make sketches is i just start with a simple stick skeleton with balls to indicate where the joints go. Then I add on simple shapes. I don’t do the thing where you place extremely simple shapes then “sculpt” them down (that’s too hard for me) just rudimentary body shapes. Use lots of circles.
For pony, the last time I drew one I made a circle for where the flank would be, the chest area, and the head. I’m assuming art academy ran you through a few ways to do it, honestly just do something that works for you.