Using the 3/4/5 Triangle    
 

Use string lines to represent the outline of your deck. Place stakes or batterboards,made of 1x3 or 1x4 scraps,about two feet beyond each corner of the deck. To checkfor squareness, especially for large decks, use the "3/4/5 right triangle" method. With the deck in position, it is easy to locate the footing locations.
     
Using the Deck Frame for Layout    
  Here's an easy way to locate the posts and footings without stringlines. Build the deck frame first. Clamp or tack the frame to temporary supports, square it, then drap a plumb bob fir the frame to determine the post locations. This method works well when there's enough height beneath the frame for you to dig post holes.
     
Digging Post Holes    
  In aress where the soil freezes, you maybe required to dig footings well below the frost line to prevent uplift. It may help to soak the soil before digging post holes. Try to dig a bell-shaped hole - larger at the bottom than the top. Remember, treated lumber in the ground must be rated for ground contact; anything else will rot quickly.

Digging post holes is almost always a strenuous job. To avoid back strain, bend your knees and use your legs to help lift and drive the post hole digger.
     
Pier Blocks    
  Pier blocks should be ste in a puddle of wet concrete, not just laid on the ground. Take time to level and square the piers before concrete is used. Trowel the concrete so that any water that collects will drain away from the block.
     
Adjustable Post Bases    
  Use stringlines to locate and square the post base. Tighten the nut on the J-bolt only finger tight until you're certain of the location. Then install the stand-off plate. It keeps the end of the post dry by holding it an inch above the concrete. Cut a piece of 4x4 post stock a few inches taller then the ledger. It's easier to measure the height after the post is secured and plumbed. Drive just one or two nail part way into the post before using a level and wooden braces to plumb the post.
     
Embedded Post Anchors    
  These post anchors can be placed so that the hold a post a full inch off concrete, to keep the end grain wicking moisture into the post. Guide them into place in wet concrete with the aid of batterboard string lines.
     
J-Bolts    
  To hold adjustable bases, J-bolts must be inserted into wet concrete. Use the stringlines to locate the center of the post.Wiggle the bolt in the concrete to make sure that the bolt is thouroughly embedded.