Keep in mind that it is much harder to keep the water parameters stable in a small tank. Nano tanks are usually not adviseable for a person new to the saltwater experience.
That being said, now you need to ask yourself a few questions such as, what do you plan on keeping in the tank. That will help to determine which things to get for your tank. Sand or crushed coral is the usual substrate choice. With as small as the tank is, I would go with something like a tetratec HOB
that has the heater inside the filtration.
Cycling is accomplished by tossing a raw cocktail into the water and letting nature take its course. (usually a month or so in time)
These are my suggestions, your mileage may vary