excellent.
so, youre off to a good start. in case you didnt know, bacteria is the foundation in which toxic ammonia is converted to non toxic nitrate. ammonia levels too high will kill fish. this is why the cycling is important. the bacteria can grow naturally, but if they gave you bacteria to add as soon as you put water in, that is a process in which you dont have to wait for bacteria to grow naturally.
so, if we assume that part was done, you should be ok with ammonia. with that said, if you see your water get cloudy this early, it might be an ammonia spike, in which water changes will help with that. It is very important, if you ahve not already, have your own test kit. for starters, you can get away cheap with an api test kit. it is also recommended to have a device to check your salinity as well. these two things are vital at saltwater tank keeping. if you havent already, these should be your next two purchases.
also, i would not add anymore fish quite yet. i personally would wait at least 2 weeks before you add more. this just ensures that your bacteria is setup and going for what you have. with that said, if you do get more fish, go slow at adding them. dont go and buy 3, 4, 5 or more fish and add them all at once. you will possibly run into ammonia issues because your bacteria load cant keep up.
in case you werent aware, try to not use tap water. if you are on city water of any kind, it is a requirement to have chemicals in the water to kill bacteria (chlorine), which will kill fish. in the near future, other than buying water from your LFS, a RODI water system will be useful. myself personally, i buy my RODI water from my LFS, and keep 6 buckets ready for water changes and top off. so a RODI isnt necessary, but is one of those things that most people run.
with that said, as it was mentioned before, when water evaporates, salt does not, so you need to make sure you keep your water level maintained. doing it manually is fine when it comes to a fish only. on my 20g fish only tank, i top off manually on that tank once a day or so.