I made a chain having 13 , in 2nd chain from hook, made sc and sc around, 3 sc in last sc and sc on each st on the other side and 2 sc in the last st. join.
R2- made sc in the backloop of each st., increased 2 sc in the corner
R3- 10 or so, sc in the each st, around, then made the flap, made a small buttonhole leaving 2 st, with chain over them and sc in the next row and FO.
Made a loop with about 11 ch, 10 sc for 2 rows, stitched on top putting the keychain through it.
Actually made for backpack two loops, but decided against putting those loops, as I preferred the small bag, one can put some change or tablet in it too ! or can use it to put a note !