copy contents of release/otls to any of your otl locations: for example, your houdini user folder: /home/username/houdiniXX.Y/otls (Linux) C:\Users\username\Documents\houdiniXX.Y\otls (Windows) folder (create otls subfolder if it doesn't exist) and you are good to go! (XX.Y will be your houdini version number, like 17.0 or 17.5)