Citadel Bugman's Glow Base paint is designed to give a smooth, solid reddish brown color over an undercoat and for that reason it will almost always be the first paint you use on a miniature. Shake the reddish brown paint before using (you can make this easier by adding an agitator ball).
The red-brown paint can be a bit thick sometimes and then you just add a few drops of water to 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 reddish-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 Bugman's Glow base paint.
The color of Citadel Bugman's Glow (21-18) is similar to: The Army Painter Tanned Flesh (WP1127 ); Old Citadel Tanned Flesh; Vallejo Game Color Tan (72066); Instar Sunburnt Flesh; Reaper Master Antique Rose (9139); Privateer Press P3 Khardic Flesh; Scale75 Kalahari Orange Matt.