Have an idea for a mod but I don't know jack about modding want to make a campaign set in 1258 beacause of the historic importance this was the time the Mongols took Baghdad and in 1260 another Mongol Khan took Kiev. Also Egypt was in control of the Holy Land.
I want to make historicly accurate to a point like royal families of the time. Also factions standings are much different the Mongols control land from Baghdad to Kiev, Egypt is one of the strongest factions at the time, England deals with alot of unrest perhaps add Whales and Ireland when Kingdoms comes out, etc. Also want to make it so that its much easier for the AI and player to build large armies with High Era units availible from the start. You will see better and larger armies with more interesting units rather than a bunch of spear militia.
Merchants make more money, diplomats are more effective basically I want to make a campaign where most of the stuff that was in the original game has a larger affect on the game as a whole.
Also want to create a mercenary guild that allows factions to recruit more mercenaries for battle quicker and easier especially beacause some factions units either suck or they lack things like good calvary and infantry.
I hope a more experienced modder can give me an idea of what I would need to know to make such a mod on my own.