Inspired by https://www.goonhammer.com/how-to-paint-everything-sisters-of-battle/
Paint the undercloak Red (about 3 coat)
Paint the overcloak and sleeves in 2 thin coats of Sky Grey (1:1 mixed with Thinner Medium )
Shade the overcloak with 1:4:5 mix of Sky Grey , Black and Thinner Medium
Highlight the overcloak with 1:1 mix of White and Sky Grey
Shade the undercloak with Red
Edge highlight the undercloak with a layer of Red
Highlight the undercloak with a 1:2 mix layer of Vermilion and Thinner Medium
Paint the armor with a 1:1 mix of German Grey and Thinner Medium
Edge highlight the armor (kneepad, boots, shoulder) with a 1:1:2 mix of German Grey , Sombre Grey and Thinner Medium
Paint ornaments and backpack logo with Gold
Paint the armor rivets and chains with Silver
Paint leather details with Red Leather
Paint shoulder symbols in Sky Grey
Paint the weapon metal parts with Gunmetal Grey
Shade the metal parts with Black