Unfortunately I only have a backup downloaded from frontend which contains the database dump in textform only, so I couldn't restore it into the package based installation, because I don't know how to restore it with psql.

So I did a docker based installation, then I could restore the database as in the tutorials.

But now I don't know how ti restore the attachments into the docker container.
I have the attachments restorted in form of "attachment/file/(numbers from 1 to 22)
I could't find the path where the docker based installation stores its attachments.
Can someone please enlighten me, so I guess I can just copy my attechments into that path?

Thank you!

Found it, it is outside of the containers  /var/lib/docker/volumes/compose_opdata/_data/files/attachment/file