As a Meeting Attendee, you have controls available to you similar to the Host. While the Host is in charge of controls such as starting or ending the meeting, locking the meeting, record the meeting, etc we provide a collaborative space so in meetings you may control your own space.
This article is about the control options offered on the left panel, the Attendee List.
In the following screenshots, you are Christine as an Attendee.
The MUTE ALL button allows you to mute everyone in the meeting. This helps to mitigate a problem with audio where you are unable to identify who is causing it (f.e. echo). Muting everyone will stop the noise and then each person may unmute themselves. Then you will find who caused the issue.
You may mute one person at a time. If even your Host has an audio issue, you may mute them and allow them to resolve it and they will then unmute themselves.
You may mute yourself in the meeting. Alternately, you may mute your device such as using your own computer controls or if on the phone - mute the phone locally.
If you would like to minimize the left panel, click the arrow. This will hide the panel for a full-screen view of the meeting. To unhide it, click the arrow again.