The phone comes with a rechargeable battery. Keep the battery charged while not in use in order to maximize talk, use, and standby time. The battery charge level is shown at the top right corner of the screen.
Insert your fingertip under the ledge at the bottom of the phone and gently lift back the cover to remove it.
Align the battery contacts with the terminals in the battery compartment and push the battery down until it clicks into place.
Place the back cover over the battery compartment, then press downward until it clicks into place.