Automerge: press 'M' while the army is selected. You can press 'M' while the province is selected: then all of the armies are merged that are in the province (observing the 16 unit limit, of course).

You can also pull the units over each other: the same type will merge.

I do not know any way to split. If you have depleted units you can try the above trick.

Quote Originally Posted by LittleJohn
Ok I have another dumb question
How do you merge units? I hear lots of talk about it but havent been able to figure it out Would also be nice if I could split then since I play with huge groups and would be nice to have only 100 peasants at times.
While I am findeing the beginners guide useful it has lots of tips like I didnt know your govorners would get vices if you have high taxes no wonder I get so many vices! But most of it is common sense, basic strategy and often tells you to read the manual. And for some reason I cant download stuff from this site so I am haveing to read it online.