This function adds a home link into my nav menu, but it is added to 3 other menus I am using as well. I don’t quite understand where to add code to only display in my primary nav.
function my_page_menu_args( $args ) {
$args['show_home'] = true;
return $args;
}
add_filter( 'wp_page_menu_args', 'my_page_menu_args' );
The $args array also contains the theme location, so you can filter on that.