well, first you’d need a good side-profile, and this one is too small unfortunately (to the bottom left of the pic)

from there, import it as a BG image into SN

then make the frame aka a simple stickman, while using the image as a guide

from there you just build off of those main points (torso, elbow, hand) etc

i mean its kinda tough to explain, its similar to “how do i draw good” – there’s really no answer you just, do it