GizMap is installed like any other Blender addon downloaded from Blender Market. First, download and save the gizmap.zip file somewhere memorable. Then, within Blender, select Edit -> Preferences, navigate to Add-ons, then select Install (Blender 3.x) or the arrow in the top right corner -> Install from Disk (Blender 4.x). Then navigate to your zip file, select it, and click Install. No further setup is necessary to use GizMap!

The most common solution to this issue is that the translation/scale/rotation transform of the object is not applied. In Object Mode in the 3D Viewport, press CTRL + A, then select All Transforms. This should fix the issue, but if it doesn't, please email us directly at support@pbrpainter.com.