To register a batch of handsets on the W80DM you will need to go into the left navigation menu, click on Handset & Account then Handset Registration. Next click on Add Handset. Then go to your handset and press on Ok, Status, Handset and then IPUI Code to check the IPUI. Finally, go back to the web user interface and click on Handset & Account then on Registration Centre to register your handsets in batches.
If you only have one or two handsets to register then follow the same steps but instead of checking the IPUI, you will press Ok, Settings, Registration and then Register Handset. Then you can select the base you want to register the handset to. You will need a pin code for sharing, the default code is 0000.