Nemovir

so I am going to need to put something rough over my leg. maybe a towel. Use a stool and maybe shorten it as well. thanks.

I bought one of these, since the stitch pony I am using doesn't handle large project easily. I can not figure out how to position it other than putting it under one of my legs. it keeps slipping off my leg when I used it. I'm not able to find any video or pages on specifically how to adjust it to comfortably to use it. any help or links?