I presume you mean
this one.
This is a thin parting tool. Referring to the drawing, the shorter edge serves as a bevel, so you use it by rubbing that bevel against the wood, with the point at the end of the tool doing the cutting. Like any other tool, rub the bevel, and then raise the handle to start the cut.
I sharpen mine with a diamond hone. I first use the hone to polish the upper edge of the end of the tool, and then polish the bevel by dragging the end along the hone so as to raise a burr on the very tip.
As you cut into a spindle, the sides of the tool will rub on the edges of the cut. The friction can cause burning which can cause tars to form on the sides of the tool. Occasionally, I will use a ScotchBrite pad to remove that tar buildup, but I never hone the sides of the tool - I don't want to tinker with the thickness.
The best way to avoid that burning problem is to cut into the wood a bit, and then start a second cut just to one side of the first cut, so that the total width of the groove you are cutting is wider than the tool itself. If you can keep the sides of the tool from rubbing, you can avoid the burning.