Trace your foot on a piece of cardboard. Make sure you leave your shoe on.

Cut out the tracing of your shoe.

Take a pencil and put it between your big toe and the toe next to it. Make a small circle there.

Next make a mark at the beginning of your foot after the ankle bone on either side of your cardboard.

Your cardboard and markings should look like this.

Use a pair of scissors to carefully punch holes where your markings are.

Poke one string about 20 inches long from the top of the cardboard through the toe hole.

(The strings from a mop head are a good length and thickness.)

Next you need to poke another 20 inch long string through one of the side holes, also from the top. Take the string under the sandal and poke it up the other side hole.

Turn the sandal over so you are looking at the bottom of the sandal. Take the toe string and loop it around the side string running across the width of the sandal. Then take the end of the toe string and put it back through the toe hole.

The bottom of your sandal should now look like this.

Next, put your foot on the top of your sandal. Tie the two ends of the side strings tightly on top of your foot. Tie a knot and cut off the ends of the string.

Next you put one of the toe strings under the knot of the side strings. Tie the two toe strings tightly together. Tie them in a knot and cut off the ends of the string.

When you are done, your sandal should look like this. You can slide your foot in and out. Repeat these steps with your other foot to get its mate.