Normal (all the way towards the back of the transmitter) Less negative pitch at bottom stick making the collective less sensitive, take off, landing and precision hovering. All right side up since the throttle will go to idle as you decrease below half stick.

Middle is Idle Up 1 or stunt mode. -10 to +10 total collecive range. Used for aerobatics with a higher head speed. Now at half throttle your throttle is half open, above increases postive pitch and throttle (keeping the head speed the same but providing more lift) and below half stick the throttle goes back towards full as you pull the stick back as the pitch goes negative, used for inverted flying.

Idle 2 (all the way towards you) is more of the same, just a higher head speed for more crisper control but essentially the same as idle 1. I only use normal and idle 1 on my setups.