Before I start hammering, I lay everything out as shown to get the orientation and spacing down. I like to have part of the shelter over my tent, as it breaks the wind and keeps the rain off.
The spacing shown has worked out well for me, and is easy to do, since everything is measured by lengths of PVC. My tent is big, and this gives me one 10' section that covers the tent, then a second 10' section to extend out the front. I have my working tables, cooking stuff, and local storage in that section.
Finally, in the third section, I put up a standard shade canopy out front with some chairs and small tables for hanging out in.