Modding Help! - Zoom and Add

PLEASE HELP ME!!! :help:

I'm totally new to modding, but if anyone could help me, please answer this, or even put a link to some tutorial!!!
I've never been satisfied with the focus on British Isles until Kingdoms was launched, but even after it, I continue looking for it. If finally I can made my mod, I promise I'll enhance it with time-gained experience, and release it, hoping to aid more people who are searching for a detailed British Isles campaign.

Here's my idea: I would made a huge (not TOO big, but still huge) map of the British Isles, with kinda 30 regions for England, 20 for Scotland, 10 for Ireland and 5 for Wales. I would stay with the vanilla factions England, Scotland and Rebels, only renaming them. - Although, if you can help me on putting Ireland and Wales factions, I would be entirely glad!!!
So, only to give an idea, the campaign would start in 1066; England would begin with London and Hastings, and Scotland would begin with Edinburgh and Aberdeen.

IF ANYONE CAN DO IT, PLEASE HELP ME! :embarassed::help::embarassed: