To activate the GitHub integration click on the Info icon next to the project title either on the dashboard or on your project board and switch to the "Features" tab.
Now click on the green Add button next to the GitHub integration to start connecting your project to GitHub.
Please click on Authorize your GitHub in order to allow modifying tasks right from GitHub.
After choosing a repository you can complete tasks and checklist items just by adding the MeisterTask task token (the alphanumeric code in the task URL) to your commit messages in GitHub. Checklist items are referenced by number, starting with 1.
You will see different examples on how to add tasks in the integration dialog
Please note: Make sure all people have the same email addresses on MeisterTask and GitHub. You need admin rights on the repository to install the integration.