How to migrate all USERS from one FB installation to another?

Hi everybody!

My Raspberry 3b+ installation became unusable after a SD-Card failure. Now I did a fresh install on a new SD-Card, recovered the Backup and noticed that the users were not recovered. (I guess this feature is not yet implemented?)

Now my question is: how can I do this manually? Is there a step-by-step guide describing this process? I found this feature request but unfortunately I can’t interpret what exactly I have to do.

Thanks in advancefor any help!
J