Conference a Call To add participants to an existing call, start from Step 5. Open the Teams App and click Calls Start by adding the phone numbers of the contacts you wish to conference and click the phone number or person below Once you have finished adding your participants, click Call The call will now ring all participants and add them to the conference call. You can check current participants and add new participants to your call by clicking the Participants icon (top left in the screenshot) To add additional participants, search for their name or add their phone number e.g. 01452874000 to the search box. You can also turn the conference into a video conference by turning on your camera (next to the mute button) and all participants that are joining from the Teams App will be able to join the video too. Any participants that have been added as a phone number will continue the call as an "Audio Only" participant.