Avamar Extended Retention

We just enabled AER and added an additional Dell tape library. Unfortunately we haven't had much in the way of training or advice on best practices.  My question is when we run an export to tape from our daily scheduled backup is this a full backup or a partial/incremental backup.  We would like to do monthly or quarterly backups of some of our critical systems and send those tapes off to a secure location.

Is there a best practices PDF?  I have the User Guide

Avamar Extended Retention v7.0.2-2.5.1

Avamar v7.0.2-47

Dell ML6020 tape library