Ch 4, slip st in 1st chain to create a circle
Round 1 – Ch 3, (the next st’s will be worked into the centre of your circle) 2 trbl, ch 2, 3 trbl, ch 2, 3 trbl, ch 2, 3 trbl, ch 2, slip st into the top of your chain 3 to complete the round.
Round 2 – Ch 3 which counts as a st, then work 1 trbl into the next two stitches, into the next corner space 2trbl, ch2, 2tbl and repeat until the round is complete. End by slip stitching into the third chain from the bottom
Round 3 – 11 – Continue in rounds by chaining 3 at the start of each round which will count as a st then trbl into each st until you reach the next chain 2 space here you will work 2trbl, ch2, 2trbl repeating on each side and ending with a slip stich into the third chain from the bottom.
I have changed colours every three rounds but you can make your colour changes as narrow or wide as you like.
This will become the base of your bag. In order to start working on the sides you need to locate the middle of each side and mark the two centre stitches.
I found the simplest way to do this is by counting in from the outside on each side of your square, until you meet in the middle then marking the two middle stitches with a stitch marker. This will need to be repeated on each side as below.
Once you have marked the centre of each side, continue to work your solid granny square as before by working 1 trbl into each st, and 2trbl ch2, 2 trbl into the chain spaces from the previous round until you reach the marked stitches.
When you reach your marked stitches, you will need to skip these along with the stitch before and after as shown in the picture and trbl into the 5th stitch. Then you can continue the remainder of that side as usual.
As you continue each round repeat the process of skipping these four stitches each round.
Continue in rounds until you have a total of 23 rounds
Complete the bag base and sides by doing one round of double crochet into each stitch
Repeat for 45 rows leaving a long tail at the end.
Fold your strap in half long ways to double the thickness of it and sew together.
Place each end of your strap into your chain two space and then sew into place by folding the strap back on itself.