Deck building checklist
as md2 suggested above, download the American Wood Council's "Prescriptive Residential Wood Deck Construction Guide" and follow it. It is based upon the 2009 International Residential Code, the basis for most local and state building codes. It provides you with the information to construct a code compliant deck without the need for engineering. Now if you want to vary from the requirements of the guide then you would need (in most jurisdictions, yours may be different) to hire a professional engineer to design and demonstrate compliance with the building code.
if you have not already done so, I would highly recommend contacting your local building department and finding out if a permit is needed for your deck, and what drawings if any are needed. Don't want to get a "Stop Order" issued by the building department. The cost of the permit really goes up at that point as a penalty for working without a permit, and they could require you to remove what you had constructed without a permit. Just a suggestion ......
Post back with any questions.
"You get what you pay for, and sometimes free costs more!"