Complex sentence: The three stars symbolise the main island groups of Tonga, which are Tongatapu, Vavau and Haapai; the Crown symbolises the ruling monarchy and the King of Tonga.
Split into simpler sentences: The three stars symbolise the main island groups of Tonga, which are Tongatapu, Vavau and Haapai. The Crown symbolises the ruling monarchy, the King of Tonga.