You can follow these steps to operate:
1. Open the imo beta application and log in to
your account.
2. Select the contact you want to call in the
contact list.
3. Click on the phone icon or voice call icon on
the contact's profile page to initiate a voice call.
4. Wait for the other party to answer the call,
and you can start the voice call.
Please note that both you and the other party
need to be connected to the internet and have
installed and logged in to the imo beta
application in order to make a voice call.