Step 1: cut out the 3 pieces of fabric in the shape of the pattern (include the lining)
Step 2: sew the lining on to one of the pieces of fabric (wrong sides together)
Step 3: sew the last piece of fabric onto the one with the lining (good sides together)
Step 4: make sure to not sew one of the sides and then insert the elastic "backwards" (loop on the inside)
Step 5: make sure you leave a space somewhere so you can flip it inside out (do not sew a spot about 1-2 cm)
Step 6: sew the elastic in
Step 7: flip cozy inside out through the space you left at the bottom
Step 8: sew shut the space at the bottom
Step 9: Top stitch around the whole coffee cozy
Step 10: measure around your cup/mug of choice and sew on the button accordingly