Or if you are just looking for a simple way to take it (like a capsule), the typical dose is 470 mg of the straight root, although some people prefer the standardized extracts (which are typically in 200 mg doses).
Now, the hard part is that different people respond differently to different products, so you might not even get enough effect from it for sleep.... you might just get really relaxed from the maximum dose, or you might not feel much of anything from it.
I'd say try it out at the standard dose to see how your body responds to it.
If it doesn't help enough for sleep, you could try Melatonin, L-Tryptophan, 5-HTP, Scullcap, L-Taurine, or Passionflower... those are also very popular products for sleep. Good luck!