Step 1: Fold and rip
Fold the paper in a half.
Rip a little rip where your fold is. One at the top, one at the bottom.
Step 2: First string
Put the string through the right hole first.
Now measure how much thread you need. The corners of the page are bent to the inside (not to much).
Make a knot at the right hole, go through the upper rip, go through the left hole and make a knot there.
Now you can cut the sting at the length you want it.
Step 3: Second string
Cut the sting at the same length as the first.
Now you can experiment with the length of the stings to find the best proportions.