Changing ownership of regions?

So I'm looking at Descr_strat trying to figure out what all needs moving in order to change ownership of a province? Say, for example, I wanted to give Poland Vilnius. What would I have to do in order to make that happen?

Well I've figured out the basics, just moving 'settlement' entries around, but I'm struggling to figure out how to move/add/delete armies and family members in a way that will actually run. I have a number of regions that I've correctly changed ownership of, but still belong to another faction because they're full of that faction's units. My only question is, which part of the entry for an army/character is its location, and where can I find the locations of the settlements? I've tried matching numbers in descr_strat to numbers in descr_regions, but none of them seem to match up.

The numbers in descr_regions are the RGB values of that region. Not the coordinates of a settlement.
What you have to do is to get in game and use show_cursorstat console command in order to get the location of a settlement. Then go to descr_strat file and just check other faction armies who are on those coordinates. Delete those armies and then replace them with your armies.

I hope this helps.

Thanks, that actually helped a lot.

Unfortunately, I got cocky, forgot to back up my files, and now the campaign map won't load (if I click 'Start' on the grand campaign screen, it just cuts back to the single player menu). I've had it happen before as the result of a simple typo, but I've changed so many things I'm not quite sure where the problem is anymore.

Question- are the RGB values neccessary for the map to load properly? I've got a hunch that'll have something to do with that, because I had messed with those a bit prior to reading your reply.