Q&A for How to Gather Fabric into Ruffles

This will vary from fabric to fabric but roughly, you'd need 2.5 times the finished length. So, if you needed one foot of ruffle, you would use 2.5 feet of fabric.

Start with the lowest ruffle down. Sew it. Then sew the next one above it and work your way up the sleeve.

Use 25 feet of fabric and follow the above steps.

The bobbin threads are the ones at the back of your fabric. The stitches at the top of your fabric are made with the thread spool you keep at the top of your sewing machine, and the stitches at the back are made using the bobbin thread.