Using these D'Addario 80/20 Bronze acoustic guitar strings is easy. First, make sure your guitar is in a stable position. Remove the old strings one by one and clean the fretboard. Then, thread the new strings through the bridge and tuners, following the same path as the old ones. Tune the strings to the correct pitch. Remember to tune gradually to avoid over - tightening. As for maintenance, wipe the strings with a clean cloth after each use to remove sweat and dirt, which can extend their lifespan. Also, keep your guitar in a suitable environment with stable temperature and humidity. If you notice any signs of wear or dullness, it's time to replace the strings.