I'm using version 1.1.12 and was wondering how I can play one song at a time. At the moment when one song finishes, the next song starts.

There is a queue mode called 'wait' or 'wait for queue' that will play the queue then stops after each song, it starts playing as soon as a song is added to the queue, you can also of course simply double click on a song to play it.

You can select this mode in the queue menu that you can find in the menubar or by clicking on the queue indicator (it depends on your layout)