Put your flannel and cotton together, right sides together and sew three edges. Flip it right side out and sew the final edge closed. Sew a running stitch around the whole thing to make it look pretty. =)
Sew five buttons to a piece of ribbon. Because this is for a baby, make super sure they're sturdy and will not come off. When they're attached, flip the ribbon over and cover the threads on the back with hot glue for extra safe-keeping.
Sew the ribbon across the top portion of the blanket. Give to a baby. =)