Using the D'Addario Pedal Tuner Plus is easy. First, connect your guitar to the tuner. Then, step on the pedal to activate it. You'll see the tuning display light up, and it will quickly show you if your strings are in tune. To use the countdown timer, press the appropriate button and set the time you want. This is great for gigs or practice sessions. When it comes to maintenance, keep the tuner in a dry place to avoid damage from moisture. Wipe it clean with a soft cloth regularly. Also, make sure to use the correct power source to avoid any electrical issues. And don't forget to change the batteries when they start to run low to ensure accurate tuning.