Enables retrieval of your Server Id, which is required for license key generation, and configuration of your SonarSource-provided License key.
The License Manager is accessible from Administration > Configuration> License Manager once you installed the plugin.
Server Id is always available at the top of this page.
Using the "Set new license" button, you can set a new License to enable or disable features in SonarQube.
The gauge is telling you the quantity of LOCs you are currently scanning and allows you to check if you are near the limit and if you need to purchase additional LOCs.
You check what are the features enabled thanks to the license you set.