That is a very very very large amount of information to cover. A quick google search turned up with this nicely written guide.
Beginners Guide to saltwater reef aquariums
If you would give that a read and then decide on what exactly you are looking for in a saltwater tank whether it be a fish only with live rock (FOWLR
) Soft coral reef, LPS
reef, or SPS
reef. Each will have its own requirements for care, equipment, and upkeep. Getting the basic idea first will help us to assist in guiding you in the right direction.