Citadel Agrax Earthshade Shade is a very thin paint designed to follow and accentuate the details of the miniatures. These types of paints are also called washes. They are invaluable to any painter. Shake Agrax Earthshade well before use.
Using a brush, remove a small amount of brown paint from the jar and onto a palette. Apply the paint to the model with a slightly larger brush, so that a lot of paint can be applied. To do this, place the tip of the brush on the figure where the details can be found and let the brown paint run into it. The paint will follow the shape of the details and give a natural "shadow". Play with the amount of Agrax Earthshade you apply so that it is not too much (or too little). You'll get the hang of it soon enough.
The color of Citadel Agrax Earthshade (24-15) is similar to: The Army Painter Strong Tone Wash (WP1135); Old Citadel Devlan Mud Wash; Vallejo Game Color Umber Shade Wash (73203); Instar Brown; Privateer Press P3 Muddy Wash.