Carefully measure and mark the positions for the shade structure posts. Make sure their positions are square across the diagonals. Measure from one corner post to the far opposite post (on a diagonal); then measure the distance from the other corner post to its diagonal opposite. The lengths should be the same.
If anchoring the posts in concrete – as with this project – use a concrete hammer drill to anchor the posts at the desired positions using galvinized post bases and expansion bolts (see image).
If not anchoring the posts into concrete, dig postholes, insert and level the posts, then fill the hole with concrete and let dry. Using a post level to make sure each post is plumb and in line with each other.
In some cases it's easiest to attach the structure to the house. In this project the structure is free-standing.