Bottom bar goes on top of the apron. There's J- nuts that slip over the holes in the bottom bar, then #14 hex head screws go up from underneath the apron into the grill bar. Just did this a couple of weeks ago. Mounted the splash apron to the radiator support and between the front fenders, then just set the grill on top and bolt from the bottom and sides. Leave everything plenty loose till you get all the bolts started, since you have to sometimes spread the fenders slightly to get the grill in.

Bob