Sorry the program hasn't been dumbed down enough for you....
This is a professional program, if you want step-by-step stick with Garageband.
Like I said, all you have to do it type Create MP3 into the online help and you get a thorough description of how to create an mp3 file including option settings and pictures.
You said:
"The manuals are complete crap."
No, the manuals are comprehensive... Logic is a deep program, if you want to learn more than 3% of what it can do the manuals are a worthwhile read.
Fortunately, Logic has not been completely Appleized and turned into Garageband pro.
Apple purchased this program and for the most part let the developers stay with thier original vision.
You said you're a musician.. so am I, if you really care about getting a professional sound it will take a little time, just like learning to play an instrument, you didn't learn overnight did you, it takes practice and time to get things right, to create the sound you're hearing in your head. Logic is an instrument capable of amazing things but you have to practice, it's not going to "play" itself for you.