Ribbon

There are seven tabs initially but additional tabs can be displayed depending on your personal Excel Options.
These tabs will look different depending on how wide your Excel application window is. Every tab is divided into "groups" and the name of these groups is displayed at the bottom.
As you make your application window wider, more and more of the commands will be displayed until eventually every command from every group is visible.
In addition to these seven tabs there are also additional contextual tabs which automatically appear depending on what is currently selected.

Ribbon Display Options

SS
Auto-hide Ribbon -
Show Tabs -
Show Tabs and Commands -

Backstage View

Contextual Tabs

Contextual Tabs
There are specialised tabs that automatically appear when a particular object is selected.

Quick Access Toolbar

Mini Toolbar

Dialog Box Launcher

Often providing more advanced features.
Hovering over displays a screen tip illustrating which dialog box will be displayed.
Double click on the Office button will close the application

Command Tip Boxes

When you hover over a command button a command tip appears to not only tell you the name of the command but also the shortcut key (if available). It will also contain other useful information to help you understand what the command does and how to use it.
For example - Format Painter, Clear Formatting