Add a full-width slider to Storefront (meta slider in example)

storefront-full-width-slider.php

// Don't copy this opening PHP tag if your file already has one.  That breaks things.
<?php

function marce_slider_before_storefront_content () {
// If the template is not the homepage (template-homepage.php), don't display.
    if ( ! is_page_template( 'template-homepage.php' ) ) {
    	return false;
    }
// If it is the homepage, add this meta slider shortcode
    echo do_shortcode( '[metaslider id=586]');
}
add_action('storefront_before_content