I reported in an email on the list that, after clearing away previous and possibly conflicting material, I found a .in file in /etc but didn't see how to make an appropriate koha-conf.xml.
The reply I received was that there was apparently an issue that "koha-create library" should, by default, behave as if "koha-create --create-db library" had been entered. However, it did not.
When I ran "koha-create --create-db library" it worked further and populated /etc/koha/sites/library with several configuration files.
N.B. I got further, but I do not yet have a real site (attempting to configure the webinstaller gets redirected to a maintenance mode page at /cgi-bin/koha/maintenance.pl); however, that may be a separate issue.
I had this same issue... I had to specify "koha-create --create-db library" rather than "koha-create library" as I was getting the following error message with the latter command:
'failed to load external entity "/etc/koha/sites/library/koha-conf.xml"'