Check drainage and grading where the deck will be built and fix any problems. Avoid disturbing the soil where the footings will go because footings need to set in undisturbed soil to prevent settling.
Set the ledger against the house wall or other solid structure and attach with lag screws. This must be done against a flat surface. Removing house siding will create a flat surface, but will create leaks, so it is not recommended. Instead, use shims to create a flat surface. When setting your ledger you need to consider your decking material height/thickness. If you desire your deck to be level with an adjacent floor, your deck should be directly below the door jam of that room when finished.
Flashing should be installed between any wood and the house (unless it is a stucco house, then no need for flashing)
Mark the foundation with string line, then mark the footing and post locations.
Cast concrete footings in the ground, then attach the concrete piers on top to hold the posts. (Check building codes for required depth for footings.) Piers can be cast in place or pre-made.
Let footings cure for at least a week.
Cut a post longer than the required length, then set it in the post anchor on top of a pier.
Check the post for plumb, using a carpenter's level. Then use a line level or water level to mark the post so it is the same height as the bottom of the joists. If the joists are to sit directly on the posts, mark the level and cut the post. If the joists are to sit on a beam set on the post, subtract that height, then mark and cut the beam.
Set the post in place and secure.
Follow the same procedure for all other posts, marking and cutting them individually to allow for any height variations.
Nail or bolt any beams in place, then attach any necessary bracing. Add any rim joists at this time and check to see they're square.
Decide on a decking pattern and the spacing of the deck boards. Starting at one end of the ledger, mark the location of the first joist. Continue marking along the ledger. Transfer the joist markings to a scrap piece of lumber, then mark the beam opposite the ledger.
Add joist hangers, then fasten the joists in place. Set the joists so the crown, or bowed side, faces up. Add any required blocking for stability.
Set posts for railings, benches, and overheads in place, and install any plumbing or wiring. Install railings that go through the deck.
Add stairs now or wait until the decking is finished.
Apply any protective finishes to the deck substructure.
Cut the decking boards to the correct length, then start laying them across the joists, beginning at the ledger and setting the convex side up if attractive. Boards can run long.
Fasten boards to the deck with nails or screws. Add spacing between the boards, as needed.
Adjust the width of the final board as needed, either by setting a slightly wider board in place or cutting one so it is less wide. Check as you go along to plan for this.
Once the final board is set, cut off any long ends.
Add any railings that sit outside the deck and any stairways not added earlier.
Add amenities, such as benches and planters.
Apply any protective finishes.