Set everything to 0 then begin messing around with everything until you start to get the hang of it...
What do you mean by 'radio-ready'. Most stations add lots of compression or something as they play it so if its not mixed/mastered well it can sound....funky, and often they might not play your song purely on this basis.
If its gonna be played on radio then you might want to get it professionally mastered. Although if its just student radio or small local one then you should be fine.
heres a good start:
How to Mix a Pop Song from Scratch / Articles / Computer Music Resources - AudioMelody