Rockwool can be hard to germinate seeds in, especially for someone new (no offense intended).
Might I recommend a better idea?
Get some beer cups (the plastic ones) and fill them with some soil less mix (or Miracle Gro, hell, just some nice aerated soil). Water it before you plant the seed, and use a pen to make an small hole about half an inch deep. Put your little baby in and cover her with loose soil. Let the soil dry out some (this will encourage root growth) before you water it again. And be careful with the water, dont wana drown the poor thing.
You wont even have to feed it (with nutes) for 2-3 weeks, and this is alot easier than rockwool, I assure you. Ive been growing for a fair bit and I still use this method, its just simple.
After about a month you can transplant it into a bigger pot. Even if your using hydro, its better to use this method to find your best females, and then simply take clones (which do quite well in rockwool).
Dont sweat it, this stage can be tricky for new growers, but once you have it down youll be good to go.