A big security feature for Zoom is the Waiting Room. Having it on allows you to grant or deny access to your virtual classroom (this is the default setting). This tip shows you how to customize the Waiting Room page to provide a message to students before you allow them in, such as, "Please ensure your name is spelled correctly (for attendance) and that your microphone is off to not disturb class when you enter." You can also include an image, if you would like.
Log into the Zoom site and click "Settings"
Next, click "Customize Waiting Room"
This brings up a window where you can change the description of the meetings, add information or and icon. One thing to note is that the images you upload need to be smaller than 400px square which is relatively small.