How to assign a telephone extension to a user

• Open Resource Manager.
• Navigate to Telephone Management > Extensions.
• Double click the extension on the right. You can search for an extension by clicking the search button     in the bottom right and entering a few characters of the extension number (or PBX name or assigned user name, etc).
• In the Assigned to user drop-down, choose the user to which the extension will be assigned. To search for a user, click the button next to the drop-down. 
• Click OK.