Diatoms on the rocks and seems to be some cyano in the front there near the glass..
Welcome to a normal new tank..
Had you not put corals in the solution to that new tank cyano is simple (turn off the lights)..
But thats nothing to be worried about at this point and it can just go away on its own.. diatoms/green film algae/cyano are very common "ugly" stages of a new tank.. Some get one of those, some get 2, some get all.. Its normal though..
You can simply carefully siphon it out with water changes for now..
Other than that.. just wait and see what happens..
again.. pretty darn normal so don't freak out..