It is not safe to add fish after 3 days. It can take upwards of a month to cycle a tank. The cloudiness is normal and will clear on it's own.
Since this is obviously your very first aquarium, I'll give you some really good advice. If you don't want your fish dying all the time, go to a book store, pet store, or your public library and get a beginner's book or 2 about aquarium keeping. It will explain all about cycling the tank (you need to add an ammonia source for the cycle to start), how to know when it is ready for fish, and everything else a competent aquarium keeper should know. The cost won't be more than a few fish would be, and will be priceless in teaching you how to manage your underwater environment. It's the single best investment in an aquarium set-up.