Welcome aboard! I'm here in Seattle and have done a lot of mask making.
First thing, is quilting is really not all that complicated to start with. We take two pieces of fabric and put them together, then put those with the next. I am self taught, I started when I was a senior in High School (some 40 years ago now). Typically we use a 1/4" seam allowance, the big thing is that you learn that and are consistent. It seemed so small when I started, being used to a huge garment 7/8ths allowance. I'd just cut your scraps into a consistent size/shape and start sewing them together. Keep your stitches fairly small, most machines with a default stitch are too large (so my Bernina defaults to something like 2.25 but I use around 1.8 for quilting). You should never be able to easily pull apart entire stitches from the end seam.
The worst thing that happens is you learn something and make something warm/comfortable for someone or at least the dog
PS: My neighbor has really enjoyed making masks for his family with the vintage machine I loaned him. He's a construction guy who just had a shoulder repaired and this mask making is giving him ideas that maybe he can make drapes or other commercial sewing and/or may have a new hobby himself!