I did the instructions in the corners correctly I think. I couldn't really figure out the "chains" on the side edges, so I think I skipped some loops/chains, whatever it's called...and so it pulled tight and curled in. The chains worked back and forth are obvious, but I still don't understand how the border works on the side edges. I'll look for vids on youtube this week to see if I can figure it out.
I do still really like how it came out. It's soft and cushy, and works great.