From the Keypad tab, enter the desired 10-digits number then tap Phone icon .
Don't prefix the dialed number with a “9” as is currently required with a traditional PBX (Private Branch Exchange) system. If a “9” is accidentally added, the call fails and you receive an error recording.
Tap NewLine (located at the bottom-right).
From the Keypad, enter a 10-digit number then tap Phone icon .
Drag the preferred call to merge.
When the image below appears, both calls are in conference call.