Whoa, thanks for all of the replies, everyone.
I decided to look up some tutorial videos for Doom II, and everything shown in there seemed simple to make. Anyway, that same night, I actually dreamt I was making and playing my first map I made with a friend using Eduke32 ( I guess watching Doom tutorials triggered the dream). It wasn't all that great of a map and the textures were very plain -it was a partially flooded temple level with a lot of pillars and rolling barrels with mutant creatures inside of them that would come up to you and attack- but it felt pretty cool being able to play it.
Nonetheless, Eduke32/Maptser tutorials are all mostly text-based,
but it seems easy enough to do (I think) with a little bit of creative thinking based off of what is shown in the tutorials. They seem to just cover mostly the basics; but from what I've read and seen, they're more for you to lean as you go than it being spoon fed to you. I think it's better that way so you can have a eureka moment when you figure out something that you've been in pursuit for a solution for quite some time -more meaningful, I guess you could say.
-Comrade Nuclear