Ensure you start with a 40mm gap from headboard to the furthest back part of cab.

Insert chassis stiffener as per video & line up with holes in center of slots to allow a little front to back movement incase you need to move to get that 40mm gap.

Insert 2x supplied M12x30mm zinc bolts with flat washers on chassis mount side & a nyloc nut on the stainless stiffener side.