Download by going over to the Releases section just on the right pane of this webpage. And then open Blender > User Preferences > Add-ons > Install, go to the zip file you've downloaded from this page ...

This add-on was designed for Blender version 2.8-4.1 (though not all previous versions may be fully supported). For Blender 4.2 and onwards, please see the new Mesh Kit extension. Adds object space ...