1. Take your backpack and cut out a piece of foam core that will fit inside.
2. Use the foam core to trace an identical piece on the fold of the batting.
3. Use the base shape as your pattern and trace out two pieces on fabric.
4. Allow an inch or so for seam allowance, and for wrapping around foam core base.
5. On one side, figure out the placing of the elastic and how much give you need depending on the size of your dinnerware (Recommended to place the silverware at the bottom)
6. Pin them down and sew into place.
7. Sew the two front and back pieces of fabric together inside out, leaving space to insert the base shape, and then turn right side out.
8. Use tacky glue to wrap and adhere the batting to the foam core.
8. Insert the base into the cover.
9. Finish sewing.
10. Add to backpack
Optional: Add two elastic straps to the side of the backpack for your picnic blanket.