Hi, Linda. I think that any forum is the wrong place to go for this kind of information. We don't know where you are, what your weather and geologic conditions are or anything else, let alone have seen the site. The place to start is with a local architect and he should have his plan reviewed by a liscensed structural engineer. He can also suggest which contractors in your area you should consider. There are also many code issues with building a 6 foot high deck and you will have to have a building permit. Your local building authorities will probably not issue a permit without well detailed drawings and several inspection visits to check the progress. I'm sure that there are many other points that I have overlooked but you should start with a local architect. If you don't believe this, call your local building authorities to see what they require.