Many ways to "skin a cat".For my ground mount, I dug holes, installed vertical pipe , concrete, let dry/cure for couple days. Then laser level I marked pipes at proper height and cut each pipe off at the mark so they were all level with one another. To get spacing right from front row to back row of pipes, I made a spacer using 2x4's , and that kept the distance exact. The wood spacer I made one for each set of poles and laid the wood on the ground flat, and it kept the front to back spacing exact dimension. I did this before pouring concrete of course. Not sure this was best way but it's what I did and it worked well for me.