Proxmox: Snapshots source?


I got a question about the snapshots app.
I got a Proxmox-Server with ZFS filesystem. Then I created a LXC-Container and installed Nextcloud in this and made a mount point of my ZFS-Pool in this LXC-Container where all my data are stored. I can see the data from the host, but what do I have to set for the path in the app?