YOU WILL NEED:
HERE is the template I made, feel free to use it. However, it is for a small zipper so you might want to adapt this template to your own zipper size.
Trace and cut around the felt and the rectangle off the middle following the straight lines.
Use pins to secure the zipper in place in the middle and sew following the dotted lines. Fold the purse in two and sew all around, for this: you could either use a blanket stitch or a simple stitch.