After you've entered your meeting (see "Zoom - User Guide" for starting/scheduling a meeting) a window will pop up asking you how you want to join the conference.

Join by Computer Audio

To use the computer microphone (if applicable) and speakers click on "Computer Audio" and then "Join with Computer Audio".

Join by Phone Call

To use your phone, click on "Phone Call" and then dial one the the numbers listed. In the phone call you will be prompted to enter the "Meeting ID" and "Participant ID".

In your Zoom meeting, click on the "Mute" icon in the bottom left corner.

Note: A hotkey can also be used to enable/disable microphone. Press ALT + A to enable/disable the microphone.

In your Zoom meeting, click on the "Unmute" icon in the bottom left corner.  You can also hold the spacebar on your keyboard to temporarily unmute your microphone.

Sometimes you may need to switch the microphone that is being used.  For example, if you are using a laptop that has a built in microphone and you plug in a higher quality microphone you will want to switch to that one.

In your Zoom meeting, click on the "^" icon in the bottom left corner next to the microphone.  Under "Select a Microphone" click the microphone you want.

By default you will join the meeting with your video connected unless otherwise set by the presenter.

In your Zoom meeting, click on the "Start Video" icon in the bottom left corner.