For the front bottom piece and the back piece, match front pieces with right sides together.
Sew and attach elastic along the marked areas- the leg holes for the front bottom, and the leg holes and waistline for the back piece. Attach your elastic to these same places.
Notice that the waistline of the front bottom piece is left open! The sides and the gussets for both pieces are also untouched.
We recommend using regular polyester thread and either a 3 or 4-thread overlock stitch. If you don't have an overlock machine, don't worry! You can use a zig zag stitch instead. More on that in this video.
Elastic can be sewn using an elastic foot to sew and attach elastic in one step, but if you don't have one then you can break the process into two steps, first sewing the fabric together and then going back and attaching elastic.
Sewing elastic can be tricky and you might have some questions! To get all the information you need in one place, we recommend watching the elastic series on YouTube. It answers all sorts of questions, goes over how to sew elastic, and also demonstrates some troubleshooting in case you run into problems. You can watch that here: https://bit.ly/3xk2VIJ