Some doc for reprepro, createrepo

Hi,
I am running SuMA 5.0 on Sle Micro 5.5.
I am trying to create my first debian custom software repository.
Doc is somewhat scarce and looks like written for insiders.

OfficialDoc

You can only add a repository to the SUSE Manager with the Web UI if it is a valid software repository. Check in advance that needed repository metadata are available. Tools such as createrepo and reprepro are useful in this regard. mgrpush can help with pushing a single RPM into a channel without creating a repository. For more information, see the man pages for createrepo_c and reprepro.

Where do I find more doc on createrepo and reprepro?
I have seen createrepo --help and reprepro --help - this is not documentation, just a reminder of options, does not really explain much.
I am lost.

Thanks for any hints.