Relatively quick job once you have worked out which piece goes where!
As you avid readers will be well aware, I purchased the pre-cut carpet set from GBS which I have to say has been a worthwhile investment and saved alot of grief in cutting carpet to size. Yes there is an element of trimming required but Its minimal.
Sequence for gluing in:
Back of seat panel
Left & right shock tower sides
rear Panel piece (goes round sides as well)
My Wife found some exceptional strong carpet spray adhesive on one her craft shopping trips and it was excellent, in hindsight easier than applying with the brush. Spray both the carpet and the panel area the carpet is being stuck to, leave for a minute and put them together. There is little time for maneuvere as it "grabs" quickly so be sure you are happy with the fit and practiced positioning before opening the glue .
Any over-spray on the chassis, carpet can be removed with some turpentine substitute ("Turps")
The hardest piece is the rear panel piece, as you need to centralise it and work centre round either side so it confirms with the shape of the rear panel.
In hindsight I should have applied the rivnuts (which hold the wheel arches on) after the carpet had gone in but it is not a major issue just provides a less flat surface for the carpet to adhere to the glue.
When it has hardened the rear panel needs to have the fuel filler cap holes re drilled through the carpet, so the filler cap can be fixed back into position