Adding Array to Firestore document

Hello, I am trying to automate acuity scheduling by sending the data coming from appointments to Firestore. My scenario looks like this:

What I am trying to achieve is to transform the data that come like this from Acuity:

In Firestore documents that look like this:

Obviously my approach is not working, and I read that I might need the Array Aggregator but I do not understand it very well and can’t seem to make the connection properly to get the desired outcome.

Hey, were you able to resolve this? Having issues with the “pattern” not being valid for the array parameters.