the code wriiten in bootstrap 4 .i want to dynamic this header with walker class? help me?

<ul class=”navbar-nav ml-md-auto”> <li class=”nav-item”> <a class=”nav-link” href=”#”>Link</a> </li> <li class=”nav-item dropdown”> <a class=”nav-link” href=”google.com”> Dropdown</a><span class=”nav-link dropdown-toggle” href=”#” id=”navbarDropdown”…

How i dynamic wordpress header menu? the html is in the body..this is situated in header.php

<div class=”collapse navbar-collapse” id=”navbarSupportedContent”> <ul class=”navbar-nav ml-md-auto”> <li class=”nav-item dropdown”> <a class=”nav-link dropdown-toggle” href=”#” id=”navbarDropdown” role=”button” data-toggle=”dropdown” aria-haspopup=”true” aria-expanded=”false”> Dropdown…