I like the fact that there are two different grits (can be seen as two colors). the black rubber feet stick to the kitchen granite top like glue. The 1000 does a pretty good job of getting a knife roughly there and the 4000 puts on a fine polish for razor a sharp edge. I would go the extra step of stropping the knife after the grinding operation for an extra sharp edge.
Start off on the rough grit side of the stone. Check the grit on your stone, or the packaging that came with the stone, to identify which is which. In general, whetstones and diamond stones each have different grits on either side. The rough grit side is used to grind the steel down, while the fine grit side is used to sharpen or hone the knife. The grinding process comes first, so you start on the rough grit side.
Whetstones may be natural or artificial stones. Artificial stones usually come in the form of a bonded abrasive composed of a ceramic such as silicon carbide (carborundum) or of aluminium oxide (corundum). Bonded abrasives provide a faster cutting action than natural stones. They are commonly available as a double-sided block with a coarse grit on one side and a fine grit on the other enabling one stone to satisfy the basic requirements of sharpening. Some shapes are designed for specific purposes such as sharpening scythes, drills or serrations.