Extension package is not generated yet - it needs merging of pull request and improving icon and documentation. It is not a lot of work, so I hope it’ll be done soon.
In the meantime, if you want a preview of how the extension will work then you can download all the files (clone the repository; or download as a zip and unzip to a local folder) and in Application settings / Modules add the directory that contains PedicleScrewSimulator.py to Additional module paths.