When fly sparging you want to do some recirculation before you start, just to get your grain bed to settle a bit and clear some of the sediment and bits of grist. Then you start to add water to the mash and drain it out at of the mash tun at an equal rate (I think about 1 qt a minute is correct or sufficient), and keeping the water about an inch above the top of the grain. Do don't stir using this method because the constant movement of water in/out from top to bottom removes the sugars from the mash evenly (this also depends on your mash tun setup). Stirring disturbs the grain bed. This is my best understanding, though I know some drain the wort from their tuns first, then refill their tuns and continue with the fly sparge technique.
In batch sparging you add volumes of water in equal amounts all at once, stir the grist, recirculate and drain until empty. You repeat until you have your boil volume (usually 2 or 3 times depending on the grain bill and equipment). It's faster than fly sparging, but many say unefficient compared to fly sparging. I batch sparge and hit my numbers every time now, where as with fly sparging I was getting inconsistient numbers. As far as which is actually more efficient, I don't know. I batch sparge, it's faster and if I lose a bit of efficiency, so be it. It's working for me.
To be fair though, fly sparging is supposed to be the more efficient method, which is debateable, I understand. Just pick a technique, develop it and see where it takes you.
Hope this helps.
Cheers.
Roman