Using this CR1216 3 - volt lithium battery is easy. First, make sure the device you're using it in is turned off. Locate the battery compartment, and carefully insert the battery with the correct polarity (usually indicated inside the compartment). Close the compartment and turn on your device. When handling the battery, avoid dropping it or exposing it to extreme temperatures. Keep it away from water and fire. If the device stops working properly, check if the battery needs to be replaced. Store the battery in a cool, dry place. If you're not using it for a long time, it's a good idea to take it out of the device to prevent any potential damage.