So, I'll take you through the process.
I found a backing large enough and laid it out. (It had to have these additional features: not clashing with the binding fabric I'd already chosen and not being so dark it could stain the wall.)
Then I added some batting. (Leftovers from Cielo). Then I laid out Liberty Bears on top.
I cut the whole thing--top, batting, and back 1.5" from the edge of the stitching. No question that this was the scariest part!
I pinned around the whole thing every inch, as Theres recommends.
I machine-sewed down the binding, like these instructions at About.com.
I flipped it over and sewed down the binding by hand, using the invisible stitch.
I sewed down two large and otherwise useless stitch markers on the back for hanging it up.