In order to be admitted into a Beepboop Drill, your Zoom display name must match your registration name. Here's how you do it:
A Participants bar will appear on the right side of the screen. Hover over your name and a "More >" button will appear.
Click on the "Rename" button that will appear after you click on the "More >" button.
Enter your new name in the "New Screen Name" field and be sure to have the "Remember my name for future meetings" checked.
After clicking the blue "OK" button, your new name will appear.