(If you need to catch up: Part 1 and Part 2)
Trace the circle onto a piece of lightweight fusible stabilizer. I always have a bolt of Pellon 960F in the house for making T shirt quilts, so that's what I used.
Pin right sides together: the rougher side of the stabilizer is the right side, so have that facing the right side of the fabric.
Pull the the fabric through the hole. You will have a circle with the right side of the fabric facing up and the right (rougher) side of the fusible stabilizer on the back facing down.
These pictures were taken from the back of the completed blocks (before basting and quilting).
Baste and quilt to finish.
My sampler turned out about 18 x 54"