Based on Cult of Paint scheme with some alterations. Make sure to hit the whole mini with the White armor steps 1-4. You will use it as a value sketch under the green of the helmet.

White Armor

1. Prime Black
2. Airbush all over Dark Sea Grey
3. Airbrush Ghost Grey from side and top. Avoid shadows.
4. Airbrush Flat White highlights mostly the top and focal point/angle of the model.
5. Airbrush Acrylic Gloss Varnish . Important to make sure a good coat to ensure wash runs to recesses.
6. STOP - Apply decals if needed.
7. Oil pin wash Smoke . Make sure its fairly runny.
8. Clean up oil spill overs with mineral spirits after it looks dry.
9. Airbush Matt Varnish
10. Edge and Spot Highlight with HBA White + DR White Ink.

Helmet

1. Cover up white areas.
2. Airbrush Phthalo Green thin (3:1 maybe even need to go 2:1 paint to thinner)
3. Airbrush Phthalo Green with Black to darken shadows.
4. ?Highlight airbrush Phthalo Green + The White ?
5. Edge highlight under shade with HBA White
6. Glaze over highlights with Phthalo Green

Weapons

1. Basecoat Carbon Black
2. Edge and Scratchy Highlight Carbon Black + Ghost Grey

Gems and Lenses

1. Basecoat Carbon Black
2. Red Oxide
3. Orange
4. Orange + HBA white
5. Orange + (more) HBA white
6. HBA White spot highlight.
7. Satin Varnish

Cloth and Other Accessories

1. [Optional] For textured areas base coat with Black and African Shadow . E.g. Grips and handles.
2. Basecoat African Shadow or Overbrush if its a textured area. Two thin coats.
3. Blackline with Black and African Shadow
4. Highlight African Shadow + Ghost Grey

Gold Trim

1. Rich Gold
2. ?Targeted wash if their are recesses? Maybe a pin wash to keep the gold clean?

Base

1. https://eavy-archive.com/40k/ Grassy plains
2. Glue down accent rocks with PVA.
3. 3:1 PVA Glue to Water to glue down fine sand. Use a sieve or fine strainer if using sand from outside.
4. Basecoat: Flat Earth
5. Drybrush: Old Wood
6. Light Highlight Drybrush: Deck Tan
7. Basecoat Rocks: Basalt Grey
8. Wash Rocks: Rhinox Hide & Black 1:1
9. Drybrush Rocks: Medium Grey
10. Glue down cut up Vallejo WIld Moss (Small - 2mm)
11. Rim: Steel Legion Drab