Google analytics custom dimension confusion

Question

I am trying to add useful event logging to my webapp. I know it is recommended to use default google analytics events, but my case does not really fit well in the default events.

In the documentation below: why do i need to configure a map with "Index" properties? I would think that i can just use the name configured in the custom dimension in the event parameters? What does this index even refer to?

https://developers.google.com/analytics/devguides/collection/gtagjs/custom-dims-mets

Answer 1

In order to use the custom dimensions you must first define them in the Property:

The index indicates the position in the list of your custom dimension that you have defined. So in the Google Analytics snippet you will use the index of the dimension where you want the information to be contained, then in Google Analytics interface you can use the name of that dimension in the reports.