Adding Multiple Names
To add more than one name at a time, hold the CTRL key down and then click the names you require.
When you have selected all required names, you can move them using the single Move button 
.
Note: When you have added a user to a department, the department name will populate in the extension properties of that user.
Move Buttons
Move all names from Available Extensions to Group Extensions.
Move one name at a time from Available Extensions to Group Extensions.
Remove one name at a time from Group Extensions.
Remove all names from Group Extensions.