The assembly fits into the assembly housing (the bracket that holds the assembly) at an angle. You'll need to put the assembly into that bracket with the key facing more toward a 70-90 degree angle with the dash - the assembly slides into the housing at that angle, then you twist it down, counter-clockwise, so that the keyhole is facing as it normally would. That locks the assembly in place. This is how I remember doing it, anyway, as I remember the assembly had to be twisted clockwise to remove it. Hope this helps.