Citadel Astorath Red 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 red paint you will immediately notice that it is very different from normal paint due to the thickness of the paint. For that reason, you don't really need to shake them.
The Astorath Red 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 red 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 tell that the red paint has captured all the raised surfaces in all the details and really picked them out.