Help needed for sliding door lock on a Coupe

[LizardsA]

I have bought a sliding door lock for the left hand door on the inside. Can anyone help with how this lock gets fitted please? Is it necessary to cut into the door upholstery to make a slot for the lock to slide in (the upholstery has recently been done for me, but the template on the door did not have a place for any fittings such as locks) also, does the lock fasten onto the metal of the door?