SCM Instance is configuration details to connect with specific code repositories like GitHub, GitLab, Subversion etc. This information is used to check for changes in repository. Plugins can use the details to checkout, commit code as well.
To create an SCM Instance, select the Source Control tab, and click the
button. To edit an existing Instance, click on an Instance row from the list.
...
Enter values for the fields as described in figure below.
...
Click the Save button to save the changes. Optionally click the Apply button to save the changes, but remain on the current screen until the Cancel button is clicked.