there's 2 methods. Method 1 is to cut the fur in the middle of the back and pull both ends taking of the top and bottom half and working the legs out. it helps to cut off the paws it'll help the legs come out of the skin
method 2 is cutting the base of the tail then stepping on the back legs while slowly pulling the tail up taking that back part of the pelt of then removing the rest.
Meat eater on netflix has an episode about them squirrel hunting and they skin them in the end check it out
There's a small game general you can post other questions in
https://www.youtube.com/watch?v=FtspCxIfWuI 