Install
Install directly from the Atlassian Marketplace
Click the admin drop-down on your Confluence instance and choose Add-ons.
Click Find new add-ons from the left-hand side of the page.
Locate Include GitHub for Confluence via search.
Click Install to download and install Include GitHub for Confluence.
You're done!
Install by file upload
Download Include GitHub for Confluence on the Atlassian Marketplace (hover over the latest Data Center or Server version, click the Download button).
Click the admin drop-down on your Confluence instance and choose Add-ons.
Click Manage Add-ons...
Click the Upload add-on link at the top right side of the page.
Enter the location of the JAR file you downloaded.
Click Upload.
You're done!