Put Speedometer Cable in Rear hole on the back of the cluster, Tighten outer hex nut on cable in clockwise fashion onto back of cluster. The Cluster gets installed first before the cable..as the cable is not long enough (You think Ford could have figured this out, but no).
No brain surgery involved....although, You may have to be on your back with the Driver's seat all the way back and be a bit of a contortionist to get the job done.
Oh Yeah, One more thing, Hope that you are not Left Handed...lol.. and if you're 6 Foot and 250lbs.. Good Luck....You'll need it.

)
Tony K.