Clear WP Fastest Cache when a Beaver Builder layout is published

You can add PHP code that will force the WP Fastest Cache plugin to clear its cache when a Beaver Builder layout is published.

Add the following code to your child theme's functions.php file.

add_action ( 
    'after_setup_theme', function() { 
        add_action( 'fl_builder_after_save_layout', 
        array( $GLOBALS['wp_fastest_cache'], 'deleteCache' ) ); 
    } 
);

Why do you need a child theme? See this section in the article about theme installation.