Hi, first of all: start a detailed diary here.
Anyway, Rh in the beginning should be 80%, then around 70% first weeks of veg. So, buy an humidifier.
About your light, try to understand what means "ppfd" and look for the ppfd map of your lamp.
You should reach this level of ppfd on the canopy:
Seedlings: 300 ppfd
Veg: 400-600 ppfd
Flo: 600-950 ppfd (1000-1300 if you're using Co2 booster)