cloning question w/ bubble dome need help!

i just bought a bubble dome yesterday at a garden store to do my clones. it has 2 trays one solid one and the other for the clones. the tray that holds the clones sits inside of this solid tray. do i need to fill it with water at all? here are pics below..

Thanks for the help!

You need Rockwool, dirt or some type of grow medium in each spot. You water each one and the bottom tray is to catch the water run off. That just a propagation tray and humidity dome

thanks alot for the help!