Trailer hitch on a 63' long bed

[Harley1650]

I bought a Reese hicth that allegedly fits my 63 long bed stepside. I dont have the deep step bumper so it is supposed to fit. Unfortunately there were no destructions included and the receiver is in three pieces. Long story short, I can't figure out if the stupid thing is supposed to bolt to the bottom of the frame or on top or inside the rails, or how the sides actually attach to the middle.......I can't find any instructions online and the holes on the brackets don't seem to line up with anything on the frame. I bought it from flebay from Texas. The customer service sucks and is zero help. Any help or pictures or someone to come over and bolt the thing on (lol) would be appreciated!