How can I access my private keys as a guardian?

In the guardian dashboard, which you can log into using your admin password, navigate to Danger Zone at the bottom of the page and click the drop-down arrow.

Next, select "Download Backup" and click "Acknowledge & Proceed" on the pop-up to download a backup of your guardian server's key material.

You can use this file to perform a from-scratch recovery, which requires your admin password.