I'm looking for a good tutorial on how to make new enemies. Not new creatures or anything, just new hostile humans with their own names, item lists, etc, and how to add them to a certain area in the game. Thanks in advance.

You would get to the point where you can use and understand this:

http://geck.gamesas.com/index.php/gamesas_Tutorial_NPC_population

and then you would have the background to begin creating your own.

In general you would take an existing Bethesda NPC and rename it in the GECK and then click "Yes" to the "create a new object" doohickey that pops up. Then you take that and get to play with it, making it as your own. But its not so useful if you dno't know how to use the leveled lists, names. and how to put them into the game, which is what the above tutorial can help with.