The actions you can perform during a teleconference are different depending on whether you are a host or participant.
If you are the host:
Press 0: to mute/unmute call participants
Press 1: to mute/unmute yourself
Press 2: to end the teleconference
Press 3: to record the teleconference
If you are the participant:
Press 1: to mute/unmute yourself
Press 2: to raise your hand