Sources
You are looking at an older version of the documentation. The latest version is found here.
The Sources page gives an overview of all sources you have added in your instance and the total number of them, as well as the possibility to view information related to the source(s) you have already connected.
You can also add new sources here by clicking + New Source.
If you need to edit or disconnect a source, you can click the ... button on the box with the source's logo and select Edit Source or Disconnect Source. In the same menu, you also have the option to Reimport Metadata.