The Dark Blue and Deep Green Dye Module can be crafted by players who have the Artifice crew skill levelled to crafting level 200. Once you have reached Artifice level 200, the schematic for this dye can be purchased directly from the artifice crew skills trainer. This dye can also be bought from other players on the GTN, or crafted and then sold on the GTN.
When you use the Dark Blue and Deep Green Dye Module, it will dye the primary dye section of your armor Dark Blue, and the secondary part of your armor Deep Green.
All dye modules are one-use, so once you've added a Dark Blue and Deep Green Dye Module to your armor, you will not be able to remove it and reuse it later.