For example, if you want to put the factions dark_magic and elves in the same folder, you need to find your Glest directory go to techs, create a new tech folder (newtech, for example), and drop the dark_magic and elves folders (these folders hold their entire respective factions) in there. So put the faction folders in:
Glest > techs > newtech
Next, you need to copy the magitech.xml file (the file that holds the attack type and armor ratios) into newtech, and rename it newtech.xml
You should be good to go, unless some of the damage multipliers the factions use are not in the xml file, in which case you need to basically merge them together. If you crash, it will be because of this. If so, try to see if you can figure out how to merge them together.
And BTW guys, Raikuron is new to these parts, so let's at least stay on topic, if not greet him, like this: "Welcome to the forums, Raikuron!" or "Happy Glesting!".
BTW Raikuron, happy Glesting! I hope you find Glest as fun a game to play and mod as I do.