Here is a direct link to the User's Manual for your phone:
To view the Owner's Manual with Operating Instructions just use your mouse to click on the link, which is the underlined and highlighted text just above. This will open a new web browser page automatically for you and allow you to view the information at the website indicated and the contents of the Owner's Manual.
You may need ADOBE READER installed on your computer to read PDF documents.
You can download this free at WWW.ADOBE.COM
Click on the DOWNLOAD ADOBE READER button on right side of the ADOBE home page when you get there, then follow the onscreen instructions to install the software on your computer.
See page 26 of the manual for detailed instructions on HOW TO REGISTER THE HANDSET TO THE BASE.
Basically, the manual reads as follows:
Not registered appears on the handset and it does not work at all.
The handset may be deregistered from the telephone base.
Follow the steps below to register the handset to the telephone base.
1. Remove the handset from the telephone base.
2. Press and hold FIND HANDSET button on the telephone base for about four seconds until the red IN USE light turns on.
3. Then press # (pound key) on the handset.
It displays Registering... and it takes about 60 seconds to complete the registration.
The handset displays Registered for a few seconds and you hear a confirmation tone when the registration process completes.
I hope that was helpful to you, good luck and take care.