4 part. Form the bag.
Make two corners and strengthen the bottom.
Sew the lining inside the bag.
5 part. Connect the clasp to the main part.
Crochet slip stitches into the front loops of the clasp and into the back
loops of the main part. There are more stitches crocheted on the clasp, so the extra stitches need to be skipped. There are should be about 96 slip stitches in total.
At the corners of the clasp leave 3 chains, not connected to the main part.
6 part. Crochet a strap.
Work 2 SC in each row until you get the desired length.
7 part. Calculations for the main part.
Mesure the perimeter of your clasp. Crochet a sample of 20 SC in 4 rows, determine the number of stitches in 10 cm of the sample. Multiply the perimeter by the number of stitches and divide by 10. This is the number of stitches for each round of the crochet fabric. Then subtract 4 from that number and divide by 2. This is the number of chains you have to crochet at the beginning of the main piece.