First off, put some lubricant on your stone. You need to use a lubricant when sharpening your tools because doing it dry will generate enough heat that it will actually warp the blade. Typically, you should use mineral oil as a lubricating agent because it can effectively reduce the heat produced by friction, but if you are out on the field and you do not have any mineral oil handy, then water will do fine.
The lubricant does more than just prevent heat due to friction from building up, they also prevent the pores in the whetstone from getting clogged up with metal shavings; so you need to constantly apply lubrication to the whetstone so that it can actually sharpen your tool. Pour a generous amount on the stone, enough to cover the surface with a rather thick film.
Now, starting at the rough side of the stone, hold your blade at an angle of roughly 10 to 15 degrees; this will give the blade an edge that is sharp enough for daily uses, but not so sharp that you can accidentally cut yourself. Holding your blade at the right angle, pull the knife towards you with the cutting edge facing you; you can also try pushing the edge away, whichever method works. While gliding the blade over the whetstone, apply a moderate amount of pressure and keep it evenly distributed throughout the entire length; you should do this for around ten to twelve times then you flip the blade over and do the other side the same way. Continue this until the blade is sharp enough for the job you need done.
Its really that simple. In most encampments, this is a daily task. Soldiers sharpening their bayonets, tomahawks and knives and Camp followers sharpening axes, kitchen knives, scissors, and such. Much of the daily work of setting up and running a camp revolves around cutting something – wood, fabric and leather, food, etc. Having a sharp knife not only makes the job easier but also safer.