Set a Default Speaker and Microphone in Webex
Choose your User Icon at the top left of the Webex Window
Then select Settings
Choose the Audio tab
There you can select (and test) your Speakers and Microphone that you will want to use with Webex
When you have the correct speakers/microphone chosen, choose Save
Adjust your Speaker and Microphone during a call
To adjust your Speaker and Microphone during a call
Ensure that your call window is Maximized by clicking in the middle of the minimized window
In the maximized window, select the up arrow next to the microphone icon
There you can select your Speakers and Microphone that you will want to use during the Webex call