Hi, welcome to AA! SW
can be a bit confusing but if you do your research and plan carefully you will be fine. I jumped straight into SW
with almost no aquarium experience at all.
If you want to start out small, a 20G tank is a good size. Generally speaking larger tanks are easier for beginners because they have extra water volume that can make mistakes a bit less costly. The basic SW
aquarium consists of the tank, substrate (usually sand), heater, filter and/or powerheads, live rock, and lights. In a tank as small as 20G you will not need a protein skimmer. Some prefer to go natural and use live rock as their only filtration while others use filters as well--canisters or HOBs are generally good. For corals you will need strong lighting, T5 is recommended.
There is a great article here called Stock list and tips for maintaining your SW tank
that goes into depth about everything I mentioned. It should be very helpful. If you are starting out simple, I would have a FOWLR
at first and go reef once you have some experience. I think $1000 would be enough to start out.
I don't know what specific information you're looking for, so if you have any questions feel free to ask