the white diamond is a filler glaze(its designed for light coloured cars,better with blackhole or ez creme glaze for your mk2),it will hide/mask and swirls/holograms in the paintwork,it should be used first. then apply the sealant as a base coat and wax on top,or you could just use the sealant on its own or wax on its own but youll get excellent beading by using them both

id clay the car,white diamond,sealant then wax and should last you a good couple of months before needing to re apply,buy yourself a quick detailer like dodo juice red mist to top up in between waxing,hope that helps mate