There are two ways that people set up their mods to be installed. Just so you know where my knowledge level is at. I do know enough to be able to create and edit items, npcs, and dialogue, but I don't know how to script.
I consider myself an expert modder, meaning in the way of using mods, not creating mods. I will list a complete pros v cons comparison at the bottom of this writeup. If you plan on using Vortex, be sure to read this guide thoroughly before you do so as t.here are many things to consider as you mod.
For some reason, mentioning a mod manager will cause people to fly into a frenzy no matter what the game, they'll claim that mod managers break your game, they ruin your life! Well, I love mod managers, they simplify my life tremendously, and I'm here to tell you that you can indeed mod KotOR and KotOR 2 using Vortex Mod Manager from the Nexus, as long as you pay attention to what you're doing and don't expect Vortex to do it all for you.