So that's meaning plant in your tank substrate. However I wouldn't plant it, instead I would place it on your substrate and let it grow. They say plant because you can and it helps if you push the bulb in the substrate a little no more than half the bulb height, but usually if it's just a bulb it can be hard to determine what's the top and bottom. So if you just place it on the substrate with the right side up it will root into the substrate, where as if you are wrong you can just flip it easily and let it be. Hope this helps!
Also on the dirt with the bulb that's just to keep it moist and dormant. If you add that to your tank it will spike your ammonia, nitrites, and nitrates.