Corrected text:

"It is a bullroarer that I modeled from a wooden bullroarer. The different sizes I tried worked well, and the sound changes depending on the scale.

To use:

1. Tie a string of any length you prefer (recommended length is 70cm or 26.5in).
2. Tie a knot at one end for better grip.
3. Hold the bullroarer by the knot and let it hang down.
4. Make sure the string is twisted so that the bullroarer rotates, otherwise it won't work.
5. Spin it around at a variable speed (avoid breaking anything) and enjoy the sound.