main_menu.php

<div class="row navigation">
<div class="container">
    <nav role="navigation" >
        <div class="container-fluid">
            <div class="navbar-header">
                <button type="button" class=" glyphicon glyphicon-align-justify navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
                    <span class="sr-only">Toggle navigation</span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <a class="navbar-brand" href="<?php echo home_url(); ?>">
                    <img src="<?php bloginfo('template_url');?>/logo.png">
                </a>
            </div>
            
            <?php
                wp_nav_menu( array(
                    'menu'              => 'primary',
                    'theme_location'    => 'primary',
                    'depth'             => 2,
                    'container'         => 'div',
                    'container_class'   => 'collapse navbar-collapse',
                    'container_id'      => 'bs-example-navbar-collapse-1',
                    'menu_class'        => 'nav navbar-nav',
                    'fallback_cb'       => 'wp_bootstrap_navwalker::fallback',
                    'walker'            => new wp_bootstrap_navwalker())
                );
            ?>

        </div>

    </nav>
</div>
</div>