The first link 'Edit' is there for course creators and -contributors to have easy access to instantly edit the word / item that they are presented with on their screen. Simply click on 'Edit' and you will be redirected to the Course Database page.
The second link is 'Report'. Clicking it leads straight to the Course Forum where you can make course-specific suggestions and/or report errors.
'Keyboard shortcuts' simply states all the shortcuts we offer. There are a number of options for customising your learning experience. Just click on 'Keyboard shortcuts' and you will be able to read how to edit it all and set it according to your preferences.
Lastly, the 'Mute Audio' and 'Unmute Audio' are there to mute or un-mute the sound of the course you are learning. If there is no audio icon above the word / item then there is no audio file for that specific word. To report this to the course creator, click 'Report'.
I found a mistake in a course and want to report it
Delete words / ignore words I already know