If you are using rockwool you soak the cubes in pH adjusted water (5.3-5.
for 24 hours then shake out the excess water, either use the hold provided or poke another hole and put the seed in it between 1/4 and 1/8th of an inch down. Put it in a humidity dome, keep the cube moist but not soaked, in around 7-14 days you'll see leaves on the top and probably a few days later you'll see roots coming out of the bottom. Then you put them in the hydro system.