Ensure the metal top arch is oriented the correct way up and the Lidar is mounted facing the front. A common mistake is for the top arch to be flipped upside down, resulting in the LIDAR facing the back. Check the direction of the LIDAR by looking at the arrow on top.
There is a orange or black 3d printed plastic standoff post which also acts to protect the cable. The file will also be provided in 3D Printed parts page See image below
The holes in the lidar standoff can be used to store some of the thumbscrews when not in use