How to Add Search With Icon Below Main Menu on Mobile Devices

I would like to use the following code in my Child Theme functions.php file but want the Search feature on mobile devices to appear below the main menu, and I would like to use the Search icon instead of the standard search box that this code displays.

I’m not a PHP or CSS developer, but I know the “fl-before-header” value needs to be changed to something, but not sure what.

// Enable Search Feature on Mobile Devices
add_action( ‘fl_before_header’, ‘search_on_mobile’ );
function search_on_mobile(){
if ( wp_is_mobile() ) {

Thanks so much for your help!