Salesforce Flow Secrets: How to Create a Roll Up Summary

Could I do this same thing to get roll up count of Number of Meetings which is identified by the Object Event, and field Event Subtype = Event, for an Opportunity? Ie after the Opportunity was created how many meetings were there

love your solution! I started my flow on the Lead and did try to use the WhoID and WhatId on the Get related Tasks but didn't work with both because didn't have those formula fields on the Activity.. also thanks for addressing the deletion of tasks part!

Very good detailed video. Thanks for putting this out, I was looking at a way to do a similar flow on different objects.