Firstly install the ten 6mm rivnuts into the pre-existing holes under the front bulkhead.

To install the rivnuts you will need a rivnut tool or you can do what I did and use a homemade tool consisting of a 6mmx30 bolt, an 8mm hexagonal nut, a 6mm washer, and a 6mm larger panel washer

Screw the rivnut onto the bolt and insert it into the hole. Using a socket wrench and a spanner install the rivnut
Hold the 8mm nut secure with the spanner and tighten the bolt using the wrench (image is for illustration only)

If your homemade rivnut tool is clean and lightly lubricated, you will be able to feel when the rivnut's core "bottoms out". Do not compress the rivnut beyond this point. It is very easy to overtighten a rivnut. If you have the slightest doubt about whether the rivnut is fully compressed, disassemble the tool and peer into the rivnut, as you can always tighten the rivnut more later on. When you have expanded one rivnut, disassemble the rivnut tool and clean and lubricate it. This is absolutely necessary as the bearing surfaces of the rivnut tool will gall and collect tiny bits of metal and rubber. If your rivnut tool is dirty, you will not be able to feel when the rivnuts compress fully and greatly increase your chances of overtightening the rivnut.

Once the rivnuts are assembled you can then bolt on the 3 front spoiler pieces.

Next operation is to drill the holes for mounting the two side spoiler pieces.

Drill the 6 holes into the lower lip of each wing (3 either side) in position (I did them 5mm) then put the snap washers in place

Now all that is neeed is to bolt on the side spoilers and jobs a goodun

That's the front spoiler fitted securely