From here you may install a new site. You may use the joomla standard package, a commercial template demo package or a backup which includes the database and a installer.
A tutorial on how to create a new Joomla site may be found here
Own Installation Package
Installation packages should be uploaded to Storage / joomla / packages.
Deactivate Autoinstall to install your package manually. This option is recomended for some Commercial Packages and for uploading backups made by Akeeba.
Settings stated here will be changed automatically after installing the new site.