I'll work on it more and give more details on things, but it's a start.

I know this is really, really late and you probably don't check this anymore, but:

I'm playing a bit of SK: Rivals and I like it, but I really didn't like that the skeleton archers were slower than the skeleton warriors - in fact, so slow they slowed down the entire army. I don't see any good reason for it, so I wanted to mod them to have 3 speed.

How do I do that? I am guessing I should do something like copy the coreunits.xml file to the mods directory, assuming it works like an override directory, then edit the Risen Archer to have a movement speed of 3.

But that's guesswork, and I can't really find the risen archer either... help?

Yes I still check it and yes that is how you do it. Not sure where Risen Archer is off-hand, you do a search of the directory for it and see where it is.

Okay, I copied coreunits.xml to mods/data/english

I changed (finally found out they were called bonearchers) their move to 3 and saved.

It doesn't appear to be changed though.

There is an option for having mods turned on. Do you have that option turned on?