I’m slowly working on a tutorial that demonstrates the simplest things, such as “How do I make a door?”. I’m using Quake 1 as an example, but the process is much the same in Quake 2, Quake 3, Doom 3, Quake 4, and all kinds of mods and spin-off games that you can use Radiant to map for.
This is a bit like an engineer trying to explain “how does a car work”, because the more experienced level designers do this in their sleep.
I believe these tutorials are worth it, though, if we can get even a handful of people interested in making their own game levels. Hobbyist level design is a dying craft. We need to go out of our way to invite and help new people get into it.
Making your own level is a rewarding experience, even if it may seem like such an obscure thing and such a steep hill to climb. The first time you load up your own DOOM, Quake, Unreal, Half-Life or Tomb Raider level is an awesome experience. It’s like you created this entire new world to explore.
Anyway, here is the tut.