For mine I just use the supplied "Local calibre catalog", but I haven't added a password.
When you generate a new catalog listing, the name can be anything you choose. The "Catalog URL" is just that, in your description
http://hostname:8080. You could use the IP address in place of the "hostname", of course. You could try placing the password at the end, of the URL, probably separated be a comma.
With the WiFi off you can click on the supplied URLs and the error message will include the format used.
The Local calibre catalog URL is "http://192.168.ect..:8080/opds"
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I played with adding a password, using calibre preferences, and it tested OK with my PC. It gave me a name and password popup, that worked, again this is on my PC. I tried a bunch of ways to include the name&password in the name and URL entries for a new catalog, but no luck, none of them worked. I guess the guys at GitHub might have to add the capability to process password requests, if we are to be able to use them.
Luck;
Ken