You are in the perfect position to get real help. Go to
www.craigslist.com and put an add in the barter section to trade work. A guy in your specialized field will pop out of the "woodwork" in no time.
Just a thought.
Stairs are not a diy project. If you are going to do them , lay all your stuff out on cardboard first. Your lumberyard has plenty of it around.
Go to the library and get a book on stairs. Sit relax and read up on it.
Then when you have more knowledge on stairs ,we can talk the same language.
The angle of the deck part is easy. use a square to get you in the right direction, then use the 3-4-5 triangle formula to get it better.
If you measure 3 feet from one point and 4 feet to the other from the same starting point. You will end up with 5 feet between those two new marks. Making a triangle.