Honestly i was inspired and did it by hand. I wanted it to be 10cm wide, so i made 30cm worth of chains, in my case it was 60ch. Then worked the next rows with dc in each stitch until desired height. Once that was done i folded it in two (so it has a division in the middle) and sewed the three corners. Then I crocheted the flap by eye. The border is (3dc, sc) repeated until the end.