For this color scheme I think a basic spray coat with black primer is easiest to work with. I used Citadel Chaos Black.
Basecoat
I start with applying a basecoat of 50/50 Mephiston Red/Rhinox Hide. I always water down the colors and put on a couple of thin layers otherwise you risk getting a grainy surface and we don’t want that.
A dark brownish red is what you should aim for. Switch the base color to Khorne Red if you want to simplify a bit.
Evil highlight
Apply Evil Sunz Scarlett directly over the base coat. The contrast difference is high so you will need to put it on in thin diluted layers and try to blend it into highlights toward the hard edges of the armor.
Troll highlight
Continue building up the highlight with Troll Slayer Orange. Apply it in thin lines along the edges. I find that it helps keeping the brush at an angle and apply the paint with the side of the brush instead of the actual tip of it.