For knitting, you will need:

• knitting needles 5 mm;
• knitted yarn;
• thin metal crochet hook;
• lock for sewing;
• 4 mm crochet hook for closing laps.

Make 25 laps loosely.
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Make knit stitches (garter stitch) with salvage edge (remove the first lap, the last is a knit stitch).

I have 54 rows.
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Close with knit stitches with a crochet hook. Cut the thread, leaving 20-30 cm.

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Steam the bag, for laps to get smooth and tightened. You will get a piece 20 cm wide, 24 cm long.

Bend the lower part, attach markers. Pull the thread inside to the top bend. Bend the top part, fasten it with markers.
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Sew the edges, getting inner half-laps from right to left (left end), cut the thread, leaving the end.
Attach a new thread, leaving the tip on the other side, also on the top bend. Sew from left to right along the right end, cut the thread.

You will need the ends to sew a zipper.
Turn the bag out.

Temporarily, sew the zipper with a needle. I made the resulting seam with a small metal sharp hook.

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To knit bag "ears", make laps on the back side, make 2-3 rows of knit stitches (garter stitch), and then begin to narrow the lower part, skipping each second row, until you have enough laps, it depends on the belt attachment.

Close the row, knit laps with belt rings.