I found some ideas on making cloth masks and made then into PDFs:
Click here for the instructions from the CDC.
Clink here for a copy of mask instructions from Wink news
Elastic is hard to find now, You can use the thin pony tail holders. I'm using 550 paracord (100 feet for about $10). Of course as a scouter I use paracord for a lot of stuff, not just survival bracelets and belts.