Ok so I got a Orion Advantage Charger (2s lipo compatible)

I love this charger!

I was reading in the manual and it said i can flex, megaflex and step charge my 5 cell 1600 NiMh 1/8 receiver pack. But the manual gives very vague and hard to understand directions on how to use these fancy sounding charger settings.

Can some one please describe what they are, what there purpose is and how to properly use them? Thank you!