Please note that this strap does not work the same as a typical guitar strap. Because most classical guitars, vihuelas, and ukulele do not come with a strap peg, a typical strap will not work at all (unless you install a strap peg or two, but that will void any warranties on the instrument).
To use this strap properly, attach the hook to the bottom part of the sound hole (part furthest away from you). Bring the strap to the back of the guitar and around your neck. Adjust the strap for comfort. Note: you cannot let go of the instrument with this strap. This strap is designed to take the weight off of your arms, but it will not keep the instrument in place. If you let go your instrument will flip over and fall.