at first pick a bag, any bag, but not too big , you don't want to spend a week doing this makeover, something like that one
then pick a pattern, any pattern, but not too difficult, you don't want to spend a week trying to figure it out, pattern like that one
pick a yarn, any yarn, may be red. Knit a square (if fits your bag) with the pattern. just as big as half of a bag. make a rectangular bottom too, i forgot to take a picture of that, oops
make 2 sides , sew them together and attach them to the bag
crochet around the handles and there you go, bag is ready!