How do I set up Custom Field Mapping - Zendesk Support to NS

My Zendesk Support tickets have several custom fields which show as

custom_fields[*].id

on the Zendesk Support side of the mapping chart

How do I use this field to pull the data from the custom field? Do I put the Field ID from Zendesk into the brackets where the * is? Do I leave the brackets or remove them? (I've tried replacing the * with Field ID with the brackets and it doesn't bring any information over)

Any help from someone who has tried this would be greatly appreciated!

Did you ever figure this out? I'm trying to do the same for custom fields in a ticket to map over to SF.