By default, the FKX theme is the only theme with the Sticky Audio Player enabled by default. To enable this feature on any other theme, you must enable it by going to Code Snippets under the Page Builder section in the Admin Area. Find the entry that says “Sticky Audio Player” and enable the switch. The feature has now been enabled.
From there, click Customizer under the Theme section in the Admin Area. You’ll be taken to the WordPress customizer. Look for an entry that says “Sticky Audio Player“. From there, you will have the option to add your .mp3 audio, customize the volume, loop the audio and change the size & color of the play and pause icons.