Adding a 4th footer widget area

Hi,

There are currently 3 widget areas on the footer, I would like 4.

I have identified the following code is probably to change this:

if(is_active_sidebar( ‘zerif-sidebar-footer’ ) || is_active_sidebar( ‘zerif-sidebar-footer-2’ ) || is_active_sidebar( ‘zerif-sidebar-footer-3’ )):
echo ‘<div class=”footer-widget-wrap”><div class=”container”>’;
if(is_active_sidebar( ‘zerif-sidebar-footer’ )):
echo ‘<div class=”footer-widget col-xs-12 col-sm-4″>’;
dynamic_sidebar( ‘zerif-sidebar-footer’ );
echo ‘</div>’;
endif;
if(is_active_sidebar( ‘zerif-sidebar-footer-2’ )):
echo ‘<div class=”footer-widget col-xs-12 col-sm-4″>’;
dynamic_sidebar( ‘zerif-sidebar-footer-2’ );
echo ‘</div>’;
endif;
if(is_active_sidebar( ‘zerif-sidebar-footer-3’ )):
echo ‘<div class=”footer-widget col-xs-12 col-sm-4″>’;
dynamic_sidebar( ‘zerif-sidebar-footer-3’ );
echo ‘</div>’;
endif;
echo ‘</div></div>’;
endif;
?>

But I would rather you talk me through the changes to be made to the code, if possible?

Thank you

[Link redacted]