Samsung SCH-U640 User Manual page 12

Insert the top end of the battery into the phone housing
3.
using the directional arrow printed on the battery. The gold
contacts at the battery end must align with contacts on the
phone. Push bottom end of the battery down until it snaps
into place.
With the battery in position on the phone, place the cover
4.
back on the handset and turn the grooved dial clockwise
until the cover locks.
*Included
Getting Started 7