MAN OH MAN....I've been on this earth for 20 years now and just figured this out!
1. Fold the sheet hamburger style, take the two corners and tuck one inside the other
2. Fold one more time to make smaller "hamburger" take the other corner and do the same3. Lay the sheet flat, and straighten it and fold the two edges in, folding the edge with elastic in first, so all elastic is hidden
5. Continue folding until rectangle is the size you want.