To use these D'Addario XT 80/20 acoustic guitar strings, first, loosen the old strings on your guitar and remove them. Then, thread the new strings through the bridge and tuners. Tune the strings to the correct pitch. When you're playing, enjoy the rich tone they offer. As for maintenance, wipe the strings with a clean cloth after each use to prevent dirt and sweat buildup. Avoid leaving the guitar in extremely humid or dry environments, as this can affect the strings' lifespan. Also, if you notice any signs of corrosion or wear, it's time to replace the strings.