Follow the below guide for more information.
Step 1. Launch the
Phone app.
Step 2. Type in the number you would like to call then taps on
.
Step 3. Once the first contact number has accepted your call, tap on
Add Call.

Step 4. Enter the number or name of the contact you wish to call and then tap the Phone icon
to start the call.
Step 5. Tap
Merge to join the two calls.
Step 6. The two calls are now joined. If you would like to end the Conference Call tap on
