timer event

I don't think there is a special video for Timer event, you can search in appian acadamy (https://academy.appian.com/).
But what you what to know? If you post your query exactly then someone may help you here.

There isn't any dedicated video. You can read the updated documentation here tho - https://docs.appian.com/suite/help/22.1/Intermediate_Event_-_Timer.html

Feel free to post any problems you might be facing while configuring it.