Hey @thensby  - You can refer to https://lukas-oldenburg.medium.com/who-is-losing-interest-in-adobe-analytics-3-key-indicators-150b3e8b097d it is really helpful

This can be done for out-of-the-box metrics and here is a document which  outlines all the details @mac28   : https://experienceleague.adobe.com/docs/analytics/technotes/event/communicate.html?lang=en#add-custom-calendar-events-to-trends-in-workspace