I need some help with modding the game, I've read the sticky guides and reviewed the forums but can't find anything helpful.

All i want to do is change the base range of the ships to about half of what they are now. The guides say i need to make a folder but they don't say how to make it work. the closest one to helping is http://www.i-mod-productions.com/showthread.php?t=662 . the part i hit trouble is "Then, in that folder, put the attached xml file and edit it appropriately."

it doesn't say how to attach a xml, or what a xml is.

Any help is appreciated. Please and thank you.