How to set the countdown to the college entrance examination as a desktop?

How to add the countdown to the college entrance examination to the computer desktop:

Post-it notes have the countdown function

Open the computer post-it notes, and turn on the functions of embedding and forbidding moving forms on the desktop

Then open the post-it notes showing the remaining due time in the basic settings

Then you can add a post-it note to the task, and then click the reminder button below to set a reasonable time reminder for it

Then you can remind it.