Conferences allow two or more participants to communicate with each other at the same time using voice; the 'Conferences' page lists all system conferences.
To add a conference click 'Add a conference' allowing you to specify a conference name for example: 'Test Conference' also a conference number, which you add to the DID to make the number a conference number.
You can also specify a PIN for the conference so only selected people can join by clicking 'Advanced Options' and specifying a conference PIN.