Using the select box at the top of the page you can restrict the repositories shown for one namespace. Alternatively you can click on one namespace heading to show only repositories of this namespace. The search bar aside the select box can be used to arbitrarily filter the repositories by namespace, name and description.
In SCM-Manager new Git, Mercurial & Subversion (SVN) repositories can be created via a form that can be accessed via the "Create Repository" button. A valid name and the repository type are mandatory.
Optionally, repositories can be initialized during the creation. That creates a standard branch (master or default) for Git and Mercurial repositories.
Additionally, it performs a commit that creates a README.md. For Subversion repositories the README.md will be created in a directory named `trunk`.
If the namespace strategy is set to custom, the namespace field is also mandatory. The namespace must heed the same restrictions as the name. Additionally, namespaces that only consist of three digits, or the words "create" and "import" are not valid.