@smokie The simplest thing to do is to factory reset the W52P, make sure the base is running the required firmware specified here
Copy the provisioning URL from the FXS/DECT Page in the 3CX MGMT console in to the provisioning tab on the Yealink W52P Base and press Autoprovision. It will pull the EXT info you have specified under the extensions tab in the FXS/DECT page. Theres no other requirement really the guide is pretty informative. Also check the IP of the Yealink base is not blacklisted in the MGMT console.
It seems and hope he has already done something since the two last days no ?
Perhaps he needs something else than restarting from scratch each time someone read this thread. all the process is known now and in his hands, let him do some experience.
cool cool bananas and I fully agree to what you are saying - so far it has been a great experience and I am learning a new thing everyday about the pbx,