Piece of cake, just installed one. First, the hitch base should be oriented with the factory branding facing toward the tailgate when the hitch is mounted to the bed. The vertical uprights can only be mounted in two positions; one position places the hitch head a couple of inches forward of the second position option . Since you have the long bed, you can probably choose the forward position. Short bed users mount in the rearward position to get that little extra distance away from the cab. It is simply a matter of orientation of the upright pieces. Since king pin weights differ on any two rigs, I would start by mounting the vertical uprights in the middle height position, there is only three height positions. Torque the bolts to 80 ft/lb. Remove the plastic caps from the in-bed pucks, leave the plastic doughnuts in place. Rotate the base handles outward 90 degrees and install base onto mounts. Return the locking handles inward 90 degrees. You should feel resistance, but it should not take crazy pressure to turn the handles. If the handles are either too loose or too tight, adjust by removing the cotter pin and adjusting the castle nut on the handle. Before mounting the head on the base, grease the black pivot shoulders on top of the uprights. Place the head on the upright shoulders and work to rock the head home on the upright shoulders. The spring-loaded handles should snap into place when you have fully reached the operating position.
disclaimer: read and follow your manual's instruction. The narrative above is based on my experience but I am not responsible for how you may use the information to assemble and operate the hitch.