Firstly, Welcome to the Marine Hobby. Do take some time to readup deep_end's article
here to get a basic overall understanding othe hobby.
You should cycle the tank for at least 4weeks, 1week is too short unless your using liverocks & live sand from an existing marine tank. Even then, care should be taken by monitoring ammonia, nitrite & nitrates before adding your first fish/coral.
I would advise against a sea anemone since you just started, their very demanding creatures. They need strong light, good water movement & good water quality. Another major issue with anemones is for their tendency to move about to find a good spot(They don't stay where you put them), there's a chance it can get stuck and die. I've read of tank crashes caused by dead anemones.
On a final note, after cycling, do remember to stock up slowly. Although the tank has been cycled, the bioload needs to be increased slowly otherwise you can experience another ammonia spike.