How to create a 3 way conference call on an Aastra 6865i phone

How to create a 3 way conference call on an Aastra 6865i phone

How to create a 3-way conference call on an Aastra/Mitel 6865i phone

The conference button is below the display on the right side and looks like 3 people.
1) Call 1st party, when they answer, press button
2) Call 2nd party and when they answer, press button again