When fitting this grille the first thing you need to do is remove the old one. To do this follow the guide here: removing the front grille.
 

Once the old grille has been removed you will see two Torx T25 screws (one either side). Remove these as this will be the new mounting point for the replacement.

Place the old Torx T25 screw through the bracket and into the panel.

You should have received the new fixings (shown below) with the new grille.

Slide the black 'U' clip over the bracket to provide a face to be screwed into.

Place the new grille where it needs to be, then using the provided screws secure the grille to the car.