My cordless phone says "to register see owners manual for help" How do I get the phone working, it is a uniden DECT 6.0 Model DECT 1588-2

With the phone in standby, press MENU/SELECT on the base.
Move the cursor to select the Register Handset menu, and then press MENU/SELECT. Handset Registering will appear.
On the handset, press and hold # until the handset beeps and displays Handset Registering.
When the handset has registered to the base, the LCD will display Registration Complete then show the handset ID number.
If the display shows Registration failed, repeat the process again.
Note: If a handset has ever been registered to a base, reset the handset before you register it to a new base