I grow a lot of things... from sunflowers and marigolds to orchids and weed.... and I will tell you, weed is the MOST challenging thing I've ever grown - and I love it! Welcome to the delightfully frustrating, awe-inspiring, rewarding, heartbreaking, joy-giving world of weed!
You're growing autoflowers - which is all I grow... their culture is similar to but at the same time quite different from photoperiods - you can't do as many "things" to them since they're on a very set schedule and won't have a lot of time to adjust to major stress. The most important things I can tell you are these:
1. Get yourself a PH pen so you can ACCURATELY measure the PH of any liquid you give your babies. You want the range to be somewhere between 6.0 and 6.5. This will avoid so many problems down the road, I can't tell you!
2. Don't drown them in the seedling stage... they don't need more than moist soil while they develop their roots.
3. Don't start any nutes for them until they are a couple weeks old and then only start them on 1/4-1/2 strength and slowly increase
4. Always practice a water/feed/water/feed routine when you do finally give them some nutes... let the soil dry out completely before giving them something
And finally - good luck and enjoy the journey! Come back as often as needed with questions/concerns - we're here to help!