Using KMouseTool is simple: KMouseTool watches as you move the mouse, and when you pause briefly, it clicks.
KMouseTool's Smart Drag mode allows you to drag the mouse.
When Smart Drag is enabled, KMouseTool pauses after it clicks down; if you move the mouse, it waits until you stop moving before it clicks up. This way, you can both click and drag the mouse. Smart Drag takes a bit more practice, but becomes natural once you get used to it.