Use rsnapshot for nextcloud backup

Hi everyone

I would like to backup my nextcloud (run with the nextcloud/letsencrypt container) data with the rsnapshot plugin. Now my problem is, that the rsnapshot plugin can apparently only backup shared folders. Is it possible to just define the data folder of my nextcloud as shared folder without causing an issue with the nextcloud container?
If this is working, how can I set up the rsnapshot plugin to work with anacron. I need anacron, because my nas is not running all the time. It is only switched on by wol and has the autoshutdown plugin running.

And one more general question: is there a place where plugin documentation can be found? I have installed the anacron plugin, but i can't see what it does or if it is even doing anything. Also for the other plugins I use, I more or less guess what they should do and hope I am right.

Kind regards,
Patrick

Dear macom,

thank you for your fast answer. This helped me a lot.
Regarding the anacron plugin, it seems I only had problems finding the plugin. I expected it to generate a new entry in the left menu, but now I found it as a new tab in the planned tasks menu.

Kind regards,
Patrick