NwN1 (and 2) was made with modding as one of its prime features and included both a toolset as well as detailed instructions and file definitions. That said, you obviously can't expect that kind of support for games that only offer modding as a viable option for those who like to fiddle around with game files. If someone decides to write a guide that's fine and all but it seems like a large waste of time since most of the things are easy enough to understand if you just take the time.
Here are some facts:
- Most of the files are archives (opened with an archiver like WinRAR), text files (opened with any text editor), or image files (Photoshop or similar software should be able to open most of them).
- Script files are written in Lua, a simple programming language that is compiled by the game when run
- Developers are a Russian group, so while they do offer help with modding, it's mostly limited to people who speak Russian
- There are already plenty of mods floating around and the best way to learn is by example, mod files are just unprotected archives
- If you don't get something, you can always talk to a modder that does, most of us don't bite