Once you have either an active call and a held call, or two held calls, you can conference both calls together. The way that you will do this depends on the type of phone you are using:

Press the Conf softkey to place the active call on hold. Press the speed dial or Extension Monitoring button that corresponds to the extension that will be the third party in the conference. The calls will be automatically conferenced together when the third party answers the phone.

Break the calls apart by using the up and down buttons to select the call that will be placed on hold, and then pressing the Hold softkey.

Press the Conf softkey to place the active call on hold.

Press the line key correspodning to the second call you would like to conference in to create the three-way connection.

Break the calls apart by using the up and down buttons to select the call that will be placed on hold, and then pressing the Hold softkey.