Secure the boards.
You want to make sure you have adequate space for the plants between the boards. Adjust the boards into the right location and use zip ties under the rope holes to secure them. I started with a single zip tie with a loose fit, which allowed me to slide the zip tie along the rope into the right position. Once I got the right placement, I added 2 to 3 tight zip ties underneath each rope hole to make sure the boards wouldn't slide under the weight of the potted plants.