Use your pencil and ruler to measure and mark out a piece of felt 23cm x 18cm. Then cut it out.

Separate the Velcro into its two parts and pin each part to one of the longer sides of the felt. If you use a shorter length of Velcro, pin each part to the middle of each side. Sew carefully around each side of the Velcro to secure it to the felt, then remove the pins.

Sewing Velcro is quite difficult. Can you think of a way to add a flap to your case, with a fastener (for example a button, string or a press stud)?