Well, you have seeds, light, and water. You have put them together in the correct combo so far, and they have already started out. You will want to get used to watering them right now so you know how much water they will need day to day. While they are still seedlings, you should be reading everything you can find about everything they are going to need. If you are on a budget, you may not want to purchase any nutrients and just try to do a natural grow. If you can afford some nutrients, I would try to find something that is for plant health, not specific for veg or flower stages. Something like Thrive Alive, Superthrive, Mycorrhizae products, or root-growth products like Root Excelurator (expensive but effective) may work best for you. Read ALL about it!

I am on my first grow currently. I tried to learn as much as I could before starting but there are new things every single day that worry or excite me and it's a great feeling. If you want your girls to do well, learn as much as you possibly can before they start growing fast.