How to use Bootstrap Navbar in wordpress Nav Menu

So you’ve added the primary menu location

Then you can add the menu with something on the following lines (preferably in header.php):

<nav id="menu-bar" class="navbar navbar-fixed-top navbar-light w-100">
                <a id="" class="navbar-brand" href="#">  
                  </a>
                  <button style="display:block;" id="responsive_hamburger" class="hamburger navbar-toggler" type="button" data-toggle="collapse" data-target="#navbar-content" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
                      <span class="hamburger-box ">
                          <span class="hamburger-inner "></span>
                      </span>
                  </button>
                  <div class="collapse navbar-collapse float-right" id="navbar-content">
                          <?php $defaults=array(
                          'theme_location'    => 'primary',
                          'container_id'      => 'navbar-content',
                          'container'         => '',
                          'container_id'      => '',
                          'container_class'   => '',
                          'menu_id'           => false,
                          'menu_class'        => 'navbar-nav ml-auto',
                          'depth'             => 0,
                          'fallback_cb'       => 'class-wp-bootstrap-navwalker::fallback',
                          'walker'            => new wp_bootstrap_navwalker(),
                          'add_li_class'      => "nav-item mx-4"

                      );
                      wp_nav_menu($defaults);?>

                  </div>
                </nav>

The theme_location array attribute is adding this menu to the primary menu location.