Measure the fabric along your boobs, make it a little longer and wider. Depending on how thin your fabric is, you might need to do two layers.
Now set your sewing machine to the loosest stitch. And do one line of sewing on either end of the fabric you’ve just cut and gather it
Cut two thinner pieces of fabric for ties at the back and sew these to the piece you’ve just gathered. Hem the top.
Now fold the remainder of the fabric in half and put it around your body. Pin it to how you’d like it to fit. Take it off and sew it up, make sure to leave a gap for the zip.
Pin and sew in the zipper.
Now pin the top part to the bottom part and sew it. But don’t sew the back. Just hem it.
Measure out the green felt across the top of the dress and cut it. Now sew it on.
Adding a strap is optional. Measure from where the top of the dress sits to where the back of the dress sits and cut the fabric to how you want the strap, you could also add some felt to the strap after its sewn on