How do I configure a Yealink T21P Phone to access the Freepbx directory

I’ve never delved into directories on Freepbx, but I need to create a corporate Directory which can be accessed by users using the Yealink T21P voip handset.

Is this a simple thing to do? If so any signposts would be welcomed.

The objective is to allow handset users to dial other handsets by selecting the user they want by name, not extension number.