A: Top wrapping is bringing the guitar strings into the stop tailpiece of the guitar from the front, rather than the rear, then wrapping them up and over the tailpiece to pass over the Tune-O-Matic bridge.
Top wrapping reduces string tension due to the shallower string break angle over the bridge, and some players feel this changes the sustain and tone of the guitar. You can achieve the same thing by raising the tailpiece higher, though some players feel that a stop tailpiece performs better when screwed down tight against the body for maximum vibration transfer.
Why not give top wrapping a try and see if you prefer it? You won’t hurt anything on the guitar and all it will cost is a set of strings. If you like it, great! If not, switch back to normal through-tailpiece stringing.