How can I get audio in a Cisco Webex meeting?

I joined my first webinar ever. It used Cisco Webex. Except for during a 4 minute video I had no sound from the speakers. Plugging in my headphones did not help. I clicked on the Webex "Audio Connection/Call Using Computer/Computer Audio Settings/Speaker: Test" several times and I did hear a tone. Should I have been using a headset with a microphone in order to hear the audio? Thanks for any suggestions.