The larvae are attracted to the light and then you can either siphon the larvae out or scoop them out with a ladle. If you move them you must keep the eggs aerated gently with a airstone or fungus will set in. Add a heater and an airstone and you're set-up. No real biological filtration is provided. I have used live rock, but there's a chance of bacterial infection coming from it.
Ammonia needs to be monitored.
Adding Amquel or its equivalent when traces show up have been beneficial. Having a bare bottom makes it easier to clean. You may need to leave a light on the first few days til the larvae develop their hunting skills. The first 10 days are the hardest. This is where the greatest number are lost.