Citadel Biel-Tan Green 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 Biel-Tan Green well before use.
Using a brush, remove a small amount of green 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 green paint run into it. The paint will follow the shape of the details and give a natural "shadow". Play with the amount of Biel-Tan Green 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 Biel-Tan Green (24-19) is similar to: The Army Painter Green Tone Wash (WP1137); Vallejo Game Color Green Wash (73205).