Here is the link with the instructions I have made two sets so far I like to have more then needed because they sometimes stay in them all snuggled up instead of going to their litter pan to pee! grrr
I am pretty sure I found this link on this site but who knows.
The instructions were very easy to follow...my first set I made with a flannel outter fabrid and the left over fleece from their cage inside. The second has fleece inside with just a cute pattern regular material and both hold up the same and are used just the same by both pigs.