Adding boats and units in kingdoms

Hello all!
I'm new to this forum and in general to the concept of modding. After a while i've decided to play my gold edition of the game and am having a very fun time with the Americas campaign. However i find it ridiculous that only the apacheans and chicmec tribes may learn european technology, so i'd like to mod the game so as to give aztecs and mayans acces to boats and some armoured and gun-armed units. I don't want to create anything new, so I was thinking of giving them the swoed militia, the apachean mounted gunners and some arquebousiers.
If anyone could help me I'd greatly appreciate it!!
thanks in advance!
-Davil92