SAFETY ADVICE: This instructable uses sharp tools. Be careful using them. If you are not sure how to use, don't continue. NOT SUITABLE FOR KIDS.
Step 1: Tools and materials
1 - Thick cardboard.
2 - String.
3 - Rule and cutter.
4 - Scissors and awl (or similar).
5 - Pencil or marker.
6 - Glue and packing tape.
7 - Cutting mat (or another cardboard).
You will need a strong cardboard (two layers is recommended). Cardboard need to be 300 x 30 cm, but no in one piece.