1.) Dial the DID or extension number of the person you want to include in your conference
call.
2.) Once the person answered the line, dial the DID or extension number of the other caller on the Dial Pad.
3.) Proceed to click the green call button and another active call will pop up just below the first Caller.
4.) Once the call is established, click on the Conference Icon on a Caller you want to conference with, as shown in the image below.
5.) Then click the Conference Icon on the other Callers Tab to merge the calls.
6.) You will be able to see if it's successful if you see the word "Established" will appear on both callers' tabs, you can now start the conference call with the other users.
7.) To end the call, just press the end call button (red phone icon).