<human>:  I want to know how to auto-tune a guitar.
<bot>: To auto-tune a guitar, you need to use an auto-tuning device. Some popular auto-tuners for guitars are made by Boss, Peterson, and TC Electronic. To set up the auto-tuner, start by attaching the device to the guitar's input jack and making sure it is powered on and connected to the amplifier. Once the device is set up, use the built-in tuner to choose the tuning you want and strum the strings one at a time while adjusting the tuning knobs until each string produces the desired sound.