Take the front mount and fasten to the chassis using a a zinc M12x35 hex head, flat washer on top, square washer on the bottom and a nyloc. 

Complete the same steps on the other side of the chassis.

Place the chassis cross stiffener in front of the x2 front chassis mounts like so. 

Take the fuel filler cover and bolt to the cross stiffener and chassis mount using x2 M8x25 hex heads with washer on both side and a nyloc like so. 

Take the PHEV side bracket and bolt to the cross stiffener and chassis mount using x2 M8x25 hex heads with washer on each side and a nyloc like so. 

Your chassis mounts should be looking like this. 

Make sure the looms are on the inside of the chassis mount. 

Fasten the rest of your chassis mounts using zinc M12x35 hex heads with a flat washer on top, square washer on the bottom and a nyloc. 

Your chassis mount set up should be looking as shown. 

Lower your tray onto the chassis mounts. 

Place chassis mount stiffeners inside the chassis runner where each of the chassis mounts will bolt through. 

Bolt your chassis mount to the tray using zinc M12x35 hex heads with a flat washer and nyloc. 

Fasten all bolts. 

Fasten the bolts that hold the cross stiffener and chassis mounts together. 

Your tray is now mounted to the chassis.