Programs you will need
K-GFF Editor - to edit the .are, .git and .ifo files
Kotor Tool - to construct the .mod file
You will be able to use many of the example files I have uploaded for this process, I will link to them here when I have rewritten this tutorial to be more comprehensive.
The idea is to help streamline the process of module creation for both KotOR games, by making assets easily viewable for users using the NWN Model Viewer which is a really handy tool.
There are a lot of maps in both games that could be used to make lots of new levels and total conversion Star Wars stories or otherwise.
In order to create a new level all you have to do is edit the relevant .are, .git and .ifo files for the level to correspond with what you want, to begin with you will have to warp there but I will slowly be writing a lot more tutorials that will cover everything I learn throughout my KotOR modding experience to help others create great content for this amazing game.
To do this you will need to open those files with the K-GFF editer, after editing them you will need to use Kotor Tool to construct the module the ERF button offers this option, then save your file as "levelname.mod" making sure to include the ".mod" file extension, change the dropdown to "MOD" then add the relevant files you will usually want the .are, .git, .ifo and perhaps .pth file which have been included in many of my files, as well as .utd for doors if you want them.
You could also duplicate and rename the .mdl, .mdx and .wok files to potentially create totally new levels with entire re-skins using the same map but not reskinning the map already in the game, to do this I will have to add a little bit more to this tutorial but I believe it will involve editing either the .mdx or converting to ASCII and editing the texture list.
I will make this tutorial much more in-depth when I get some time, adding photos and more as well as many more tutorial to come, I look forward to seeing whole new galaxies in the future made by lots of people.
There is also a short tutorial on how to port modules from TSL to KotOR that I wrote on Deadlystream.com
I will be re-writing it at some point as well as posting it here on the other mods page, each relevant tutorial for KotOR 1 or TSL will be on my mods page that applies to the relevant game you are looking to mod.
Tutorials should provide a good overview of what to do in either KotOR game but the process may be slightly different, all of the resource files I will release can also be combined into one package in order create new levels for my Expanded Galaxy Mods for both games in the KotOR series.