I did not. I didn't catch that part of the set up. I have it checked now, I made some changes to the template and saved it. When I restarted the phone, the changes were not there.
I deleted the phone, did a network scan and added it back, selecting the phone model and template that I created for it.
I then went to Extension mapping and selected the phone, with to the advanced tab that I didn't see before and made sure that the Expansion Module option was selected for GXP2020EXT-1 was checked. I clicked on the Rebuilt/Reboot option and closed the box. I am not sure if I need to Save and Rebuilt first, then do a Save and Reboot. I'm trying to understand it all, read the documentation, etc.
I think the key is the order of the process which I'm still trying to figure out.
But so far, nothing I do seems to work. I do have programming in the phone itself. Should I need to wipe the phone completely and try again?