Citadel Sylvaneth Bark Dry Paint is specially designed to paint miniatures very quickly and easily using a technique called drybrushing. It's really easy to do this, and it looks great because it really makes the details on your thumbnails pop out.
When you open this brown paint you will immediately notice that it is very different from normal paint because of the thickness of the paint. For that reason, you don't really need to shake them.
The Sylvaneth Bark Dry paint is best applied with special brushes for dry-brushing, these are much coarser than regular brushes, much stiffer. That is important for this technique. Apply some brown paint to your brush and blot it on a piece of kitchen paper (this will absorb more paint than a smooth palette, for example). Then apply it to your thumbnail by swiping the brush back and forth over the detail. You can immediately see that the brown paint has captured all the raised surfaces in all the details and really picked them out.