Maybe I didn't made myself clear enough, or sounded somewhat rough .. but I'm not of the diplomatic type, and english isn't my first language .. .
However, as I said, all commands are there. If there's something you can't do with them, you can't do it, simple as that.
Adding a nation is one of these things.
It would require GUI changes, and therefore could only be done by the devs. But those aren't very fond of coding GUI, so we're stuck with choosing from , what, 17?, different nations.
And I don't think a modding-walkthrough would make any sense. It's not that hard to figure it out from the docs, and than there's this forum to search for the answers to those question which remain. A step-by-step walkthrough would only result in a bunch of poor, partly finished mods by those with a short attention span
