Cut out stars from your styrofoam sheet with a Styro Cutter.
Cut out square pieces of fabric at least a couple of inches larger than your star.
Make slits in the fabric to cut out the points of the star.
Use the decoupage medium to adhere the fabric to the star as shown below. Trim away any excess fabric.
Wrap the outer edge in ribbon and adhere it with the decoupage medium.
Form one string by twisting the red, white, and blue embroidery thread together. Hot glue the stars onto the string. Then hot glue the buttons onto your stars.