The dirt floor will be a breeding ground for thrips, harbor airborne pathogens, and be a source of humidity. You need to at the very least, cover it with a tarp.

If you have never grown indoors before, I don't recommend starting with that system, especially since you do not have a mother plant yet. Read the link in my siggy about starting a soil grow from scratch. You will want to start by choosing your mother out of your first crop, and mothers are very easy to keep in soil. Then when you know how to grow better, you take clones from those mothers and put them in whatever system you like.

Virtually all hydro systems that come pre-fab like that are not suited for flowering from seed.