Confusion regarding the usage of the app

I’m having trouble understanding how to use the app.

It's unclear where to upload an audio file in the GUI.
There’s a text field at the top—what is its purpose?
The buttons at the bottom don’t respond to clicks.
If there’s an option to record audio directly, I can’t find it.

Clear instructions on how to upload an audio file and use the app would be nice to have. 
