[CTS]

There is an official Editor - GEM Editor, comes with a game, you should have a shortcut for it on the desktop. You can build maps and missions in it.

Mods that change weapon fire rates, power of explosions and such, are done in notepad. Its just editing some files. I would advise you to dowlnoad one of the small mods, that does not change much, and compare the files with the original (it will also help to understand the files structure of MoW). There are few huge files in your MoW install folder, like "resource", "maps", "entities" you can open them as a .zip file and extract the needed files in your own mod folder, then edit them as you like.