Verify that you are a site administrator on the GitHub Enterprise Server source. The best way to do this is to verify that you can SSH into the instance.
Generate an access token with the
admin:orgscopes on the GitHub Enterprise Server source instance.
To minimize downtime, make a list of repositories you want to export from the source instance. You can add multiple repositories to an export at once using a text file that lists the URL of each repository on a separate line.
Article version: Enterprise Server 2.21
Preparing the GitHub Enterprise Server source instance
Before migrating data from GitHub Enterprise Server, ensure that you have the proper authentication and administrative access to the instance.