Hi @Daisy_Ramirez, sorry for the slow response.
Currently, AppSheet does not give you a simple mechanism to react to an update event and automatically add rows to another table. We should and it is much asked for and it is in the works — but we don’t have it at the moment.
So you’ll need to use some external mechanism to react to the user modifying the favorites and cause that to add the rows into the other table.
You have two different options (neither ideal):
a) you could use a workflow rule that reacts to a change in the favorites and posts something via a webhook. One thing it can do is post to Zapier where you respond to that by updating a Google sheet. Or, it could even post back to our own API and cause a row to be added.
b) you could write a scheduled appscript in Google Sheets that wakes up every few minutes, checks to see if anything was updated, and then copies the necessary data
If you are familiar with webhooks, the Zapier route might be easiest. Otherwise, the appscript might be the easiest just at the moment.