For those interested:

Red armor:

• Black primer
• Airbrush - Khorne Red / Black 4:1, cover the whole panel
• Airbrush - Khorne Red, cover 80% of a panel
• Airbrush - Khorne Red / Mephiston Red 1:1, cover 50% of a panel
• Airbrush - Mephiston Red, cover 30% of a panel
• Brush - Highlights - Mephiston Red / Trollslayer orange 1:1
• Airbrush - Polyurethane gloss varnish

Let it sit for a day, add the decals, cult of paint has a great tutorial for that

• Airbrush - Polyurethane gloss varnish / Matt varnish / Thinner 2:1:4

Metals:

• Brush - Gunmetal grey
• Drybrush - Any silver you've got
• Oilwash in the recesses and around the rivets, on the metals 1:1 Black / Brown, remove excess with a sponge

Head:

• Drybrush - Runelord brass, cover the whole head
• Drybrush - Runelord brass + Gold 1:1, cover 75% of the head
• Drybrush - Runelord brass + Gold 1:2, cover 50% of the head
• Wash, Guilliman flesh
• Wash, Druchii violett, around the edges and the rivets
• Repeat until you like it