Yep I made these, not perfectly square by any means but I love the colors and pattern from the capalana that I used.
These were really easy, just two square pieces of fabric sewed right sides together and then turned right side out and sewed around the edge with a simple stitch. You could use a zig zag stitch and that would look nice, but I prefer the simple.
Do you use a certain kind of stiff material, or do you just use starch when you iron the napkins?
The capalana fabric is kind of stiff but no you don’t need to use anything specific. You can spray starch on them if you want them stiff but its not necessary. I just iron them to give them shape.