How to Convert Bootstrap Menu to WordPress Menu

1. Register Menu from your functions.php file


     // This theme uses wp_nav_menu() in one location.
register_nav_menus( array(
'primary' => __( 'Primary Menu', 'jhilik' ),
) );

2. Add This below code to your functions.php file 

/*--------------------------------------------
17.  Register custom navigation walker
----------------------------------------------*/
require_once('inc/wp_bootstrap_navwalker.php');


3. Put the wp_bootstrap_navwalker.php  file to your  inc folder (or any place) of your theme.
You can get the wp_bootstrap_navwalker.php  from here

4. Replace the header.php code



by 


 
            wp_nav_menu( array(
                'menu'              => 'primary',
                'theme_location'    => 'primary',
                'depth'             => 2,
                'container'         => 'div',
                'container_class'   => 'collapse navbar-collapse navbar-ex1-collapse',
                'menu_class'        => 'nav navbar-nav',
                'fallback_cb'       => 'wp_bootstrap_navwalker::fallback',
                'walker'            => new wp_bootstrap_navwalker())
            );
        ?>