What's the difference between the display methods?

The Timer app includes display options for a variety of different needs:

With the My Video settings, the Timer will appear alongside your own video, such as a split screen display or with the Timer as an overlay on top of your video. Note that if you turn your video off, the Timer will no longer be visible to your Zoom participants.

If you select the Share Screen display method, press the green "Share Timer Display" button to begin sharing your screen.

Once you've shared your screen, you can adjust the Timer's size by clicking and dragging from the corner of the green box surrounding the Timer:

If you don't want your Zoom participants to see the Timer, select Only Me as your display method. You will be able to see the Timer in the right hand sidebar in the Zoom client. Only you will see the Timer this way, not your Zoom attendees.