basically following this should get you going:
Summary of the most secured way:
- install pyrevit
- create a repo containing the .tab folder and its content (the .extension higher level folder will get created by the command line) and extension.json file
- get your user to create a github account
- add them to your private repo
- have them create a github private access token
- run the command line to install the toolbar
pyrevit extend ui extensionName https://github.com/gituser/repoName.git --dest="C:\xxxx" --token=``"personnalaccesstoken123differentForEachUser"
and you can follow the explanation for the rest in the link above about the way to update from the private repo