How to Install a Strap Button on Guitalele or Classical Guitar (Must-Have Simple Upgrade)

In this tutorial, targeted at musicians with limited experience in DIY, I demonstrate how I have installed a strap button on my Yamaha GL1 Guitalele. It is a very important modification for guitaleles and it can be useful for full-size classical guitars too if you do not like those footstools and expensive supports and want to use a simple strap!
I show a straightforward method to do it, which does not even require power tools like an electric drill. The same method works for any other guitalele, ukulele, acoustic, or classical guitar.