UrBackup Docker container client volume doubt

Hi folks,
I’m about to migrate clients installed to docker clients and reading the docker compose file, I’m facing a doubt where I cannot find the explanation:
At the compose file says to define a volume /path/to/backup:/backup and I can imagine that is the path that I want to backup from the client, Am I right?
If so, I have some additional doubts:
1- Do I have to bind a path for each path I want to backup?
a. If so, how can I declare the internal container path?
2- Can I define /:/backup as a bind and on the client GUI configuration I will define each paths under /backup I want to backup?

Please, let me understand this behavior to avoid any type of issue during my migration.
Thank you in advance,