Download all files here. This includes an STL file (to 3D print) and a JPEG photo to print out as a template. The download is an external link, and will redirect you to Dropbox (April 4th).
Here are a list of the materials you need to make your own mask:
3D Printer
PETG (best) or PLA (decent) filament
Single Hole Punch
Plain Paper
Overhead Projector Film (or clear sheet-style alternative)
That's it! It's really simple to make.