Theirs a green ground wire, a white neutral wire and for some reason 3 black wires.
If the ceiling fan has three speeds, those would be wired to a 3 position switch as low, medium and high. Normally the wires would be labeled if they use the same color. If they aren't tagged, and you want to put in a speed control switch, you'll need to experiment; either at the fixture, or just wire them down to the wall switch and make your temporary connections there to see which wires go with which speeds (then TAG them!).
it could be for the lights if its an option otherwise connect all the black together to the hot wire. What does the instructions say? worst it can do is trip the breaker.
