All the winches I've had or seen have had the cables come out of the bottom. You should be able to tell when you let it out or real it in. I have used battery cables to check if the winch works. So you could do that to see wich way the cable reals up.

There will be four bolt holes on the bottom of the winch. Just use some grade 8 bolts that fit and bolt to the bumper. Power cable goes to battery, find a good ground spot and you are good.