first skull white or chaos black under coat (imo)
then UM blue, hightlight with a mix of UM blue/skull white 70/30 then add more skull white to the mix. thats highlights finished.
then the shoulder trim is dependent on the company you want, 2nd company gold, 3rd comp red, 4th green ect. boltgun you should drybrush boltgun metal over chaos black aswell as other metal bits air vents ect. then the purity seals, red at the top then a mix of bleached bone and white at the bottom. eye lenses blood red.
if you have a steady hand paint squad markings on by hand or use transfers
sorry if i left any thing out.