I recently bought a refurbished Yamaha FGX730SCA Acoustic/Electric. It has a built-in tuner, but I have no idea how to use it. There was no manual or book.
On my Yamaha (different model) there's a little round black button. If you press it, the battery light will flash once. Then play a string, and an arrow will appear telling you to flatten or sharpen the note. Both arrows will light when it's in tune.

Check the battery's not dead first
It's easier to learn to tune your guitar.
Acoustic Percussion Guitar Player
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