We'll help you through this. I'm on my 5th saltwater tank now recently downsized from a 200g mixed reef to my 12g mixed reef an have 6 years of SW
under my belt and I bet there's people on here with twice as many tanks and loads more years than me lol.
First off, how big is your tank? Next what filtration are you running? Do you use RODI
for top off and mixing saltwater? Do you have live rock in the tank, if so how much? How many inches of sand do you have and is it live? And what lighting do you have?
Also go on Wikipedia and look up fish tank cycle, that had a long detailed overview of what happens when a aquarium cycles. As far as fish you don't need them right now. And the last thing you need to be worried about is adding corals. That comes last. Answer the questions and look up the article. Please if anyone else wants to chime in please do so, let's get this person some much needed help.