The Navbar sits towards the top of every page for a given virtual machine, underneath the machine's hostname/FQDn. The Navbar acts as a series of quick links to those more frequently used pages and functionality.
The content will sit just below the Navbar and where a sidebar is used the content area sits to the left hand side.
The right sidebar contains quick access to frequently invoked actions on a given virtual machine or any of it's resources, i.e. start/shutdown, or attach/detach an ISO etc. The right sidebar may be broken down into separate lists of said actions, i.e. Actions / Configuration in respect of a virtual machine.