Thank you so much for your help!
I don’t think I did a very good job of explaining my goals here. 
I am looking to have a play button (left), when clicked this button plays music and instantly changes into a pause button (right) for ease of use. When the user uses this button a 2nd time, it will act as a pause button. As soon as it is clicked the second time, it is now back to the original state (left) of “PLAY”, so the user can use it again to play the media.
What I’ve been able to do so far is have the text change to pause and the media to start on 1st click.
I can’t seem to figure out how to make the 2nd click recognise it is now a pause button? I want it to pause media and return to “PLAY” text or image.
Does that make sense? 
Many thanks!