How do you backup a folder to Backblaze B2?

I’m using a docker container. I want to backup to a Backblaze B2 bucket.
I’ve created the Backblaze bucket.
I’ve created a Kopia repository that points to the Backblaze bucket.


How do I backup a docker non-container folder to the repository (Backblaze B2)?
The container doesn’t seem to have a path to the host folder that I want to backup.