Can I install this Fire Rated Downlight myself?

No. In Australia, all electrical work — including the installation of downlights — must be carried out by a licensed electrician in accordance with AS/NZS 3000 (Wiring Rules) and applicable state or territory electrical safety legislation. 
Additionally, because this is a fire-rated product, an accredited fire assessor must verify the suitability of the installation in the specific ceiling system before installation.