Citadel Steel Legion Drab Base paint is designed to give a smooth, solid brown color over a substrate and for that reason this will almost always be the first paint you use on a miniature. Shake the brown paint before using (you can make this easier by adding an agitator ball).
The brown paint can be a bit thick sometimes and then you just add a few drops of water on your pallet. You really don't need a lot of water. Something to watch out for is to make sure you don't apply too much paint so that you don't start to hide details.
Another important functionality of this brown paint is that it not only covers the undercoat, but also covers other colors. So if you later miss something about this color, you can easily paint over it with this Steel Legion Drab base paint.
The color of Citadel Steel Legion Drab (21-17) is similar to: The Army Painter Leather Brown (WP1123); Old Citadel Graveyard Earth; Vallejo Game Color Earth (72062); Vallejo Model Color US field sludge; Instar Mud Brown; Reaper Master Uniform Brown (9127); Privateer Press P3 Gun Corps Brown; Scale75 Gobi Brown Matt.