Include document fields in the message

My condition in the Alerting is ‘when avg(field) over all documents for last 5 minutes’. My action is to send email.
Can I include a few specific fields from these documents for which the condition is met - in the action message?
I know I have access to ctx variables but not sure how to use it for my purpose?

Hello @agenobarb, can you please try to follow example from this post