This is how it looks:
There are four main areas in the editor.
Open editors area
The open editors area will show you which content you have open at the moment and allows you to save it. When you hover over line which says "OPEN EDITORS" text you should see two icons: one allowing you to save all open files and one to close all open files.
Every unsaved open file has a little save icon when you hover over it.
The explorer area will show you all content in your site.
When you hover over your site name ("PERSONAL SITE" in the below screenshot) you see additional icons, which allow you to add new folders, new files. As a convenience it also allows you to collapse or expand all folders.
The below buttons are available when the file is open and/or when you hover over the explorer area.
The tabs area will show you which content you have open at the moment. When a file is unsaved, it has a blue dot next to the filename.
This is where you can edit text and images. A different editor will show, depending on what type of file you open.