I made my own bias tape strips
The strips went in between the two front panels
I then sewed bias along the round edge of the bag
The zip was then sewn to the bias, I used an invisible zip as it was the only red one I had, but I sewed it on the same as a regular zip.
Then do the same with the second side of the zip
sew the bag sides together from just under the end of the zip either side, and across the base.
Do the same with the lining.
Open up the cut off corners and sew to make a square base, turn the right side out.
Same with the lining!
Press the opening in the lining over by 1/4", then drop into the bag and hand-sew aroun the top.