Password Manager and App, unclear about use

I just installed the NextCloud Password Manager and the Linux client (on Fedora 39 KDE).
Strangely enough, if I open the app in NextCloud, a lot of passwords are already there? That’s handy, but still… (I did try PasKeep or what’s is name in the past).
If I open the desktop client, there’s no program. Is that expected, because it runs in the background? I searched the manual but didn’t see the answer to those questions (if I didn’t look good enough, just point me to the right info).

When the application is launched, you should see a configuration window.
Maybe you have encountered this bug: ?

Hello mdw,
I think I did. I don’t really understand what’s explained and I don’t see a solution.
Maybe it can help if I start from terminal, but I don’t know how to do that with flatpak. I’ll check it out.