To build a pergola the first thing you have to do is sink posts and level them with some flying buttresses. Then you pour cement to lock them in place.
I used 6X6 inch treated posts. After the cement dries the next thing to do is hang the support beams. Since I didn't have anyone to help me with most of this, I had to make the project doable solo. The support beams are 2X8 inch treated lumber, longer than 12 feet. Each one weighs about 70 pounds or so. You can imagine how hard it would be to hold those up and get everything level. To aid in the process I hung 1X4's and leveled them.
Once the 1X4's were up it was easy to hang the support beams and rest them on the 1X4's. I held them in place with clamps and then deck screws.
The next thing to do is to drill some 10 inch carriage bolts through the support beams and the 6X6's.
After the support beams are hung it is time to hang the rafters.
The next thing I did was to hang some 2X2's to make a nice grid.
All of the wood is treated. The lumber yard didn't have 2X2's that were 12 feet long so my father in law helped me turn 2X4's into 2X2's. Finally, to block out the Western evening sun, I hung some tight lattice.
I might need to change a few small things over time but the bulk of this project is completed. Here is a clue photo of another top secret project that is underway: