DW 8 is too old and outdated for building modern websites visually. It doesn't understand responsive web design, HTML5 or advanced CSS & JavaScript. What you see will not be what you get. Also we no longer use tables for layouts.
As an example, copy & paste the following code into a new blank document. I can say with certainty that DW8 Design View won't handle it well. Save it and preview in browsers by adjusting your window size to see how it responds.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Bootstrap 4 Starter Page</title>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!--Bootstrap 4 CSS-->
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<style>
body { padding-top: 3.5rem }
/**placeholder image**/
.jumbotron {
background: url(https://placeimg.com/1200/500/arch) no-repeat center center fixed;
background-size: cover;
}
.jumbotron > .container {
background: rgba(0,0,0,0.5);
padding: 3%;
color: #FFF
}
</style>
</head>
<body>
<nav class="navbar navbar-light navbar-expand-md bg-light justify-content-center fixed-top"> <a class="navbar-brand" href="#">Brand / Logo </a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarsExampleDefault" aria-controls="navbarsExampleDefault" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button>
<div class="collapse navbar-collapse" id="navbarsExampleDefault">
<ul class="navbar-nav mr-auto">
<li class="nav-item active"> <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a> </li>
<li class="nav-item"><a class="nav-link" href="#">Menu 1</a></li>
<li class="nav-item"><a class="nav-link" href="#">Menu 2</a></li>
<li class="nav-item"><a class="nav-link" href="#">Menu 3</a></li>
<li class="nav-item"><a class="nav-link" href="#">Menu 4</a></li>
</ul>
</div>
</nav>
<main role="main">
<!-- Main jumbotron for a primary marketing message or call to action -->
<div class="jumbotron">
<div class="container">
<h1 class="display-3">Hello, world!</h1>
<p>This is a template for a simple marketing or informational website. It includes a large callout called a jumbotron and three supporting pieces of content. Use it as a starting point to create something more unique.</p>
<p><a class="btn btn-primary btn-lg" href="#" role="button">Learn more »</a></p>
</div>
</div>
<div class="container">
<!-- Example row of columns -->
<div class="row">
<div class="col-md-4">
<h2>Column 1</h2>
<img class="img-thumbnail" src="https://placeimg.com/400/300/nature" alt="placeholder">
<p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
<p><a class="btn btn-primary" href="#" role="button">View details »</a></p>
</div>
<div class="col-md-4">
<h2>Column 2 </h2>
<img class="img-thumbnail" src="https://placeimg.com/400/300/arch" alt="placeholder">
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Debitis necessitatibus, tempora, aperiam expedita ullam laudantium consequuntur quos commodi maiores possimus fugit pariatur aspernatur sit quae, voluptates nisi earum aliquid placeat!Donec id elit non mi porta gravida at eget metus. </p>
<p><a class="btn btn-primary" href="#" role="button">View details »</a></p>
</div>
<div class="col-md-4">
<h2>Column 3</h2>
<img class="img-thumbnail" src="https://placeimg.com/400/300/tech" alt="placeholder">
<p>Donec sed odio dui. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
<p><a class="btn btn-primary" href="#" role="button">View details »</a></p>
</div>
</div>
<hr>
</div><!-- /container -->
</main>
<footer class="container-fluid bg-dark">
<div class="row">
<div class="col text-center text-light">
<p>© Company Name 2017-2018</p>
</div>
</div>
</footer>
<!-- Bootstrap core JavaScript
Placed at the end of the document so tpages load faster -->
<!--latest jQuery Core-->
<script src="https://code.jquery.com/jquery-3.2.1.min.js" integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4=" crossorigin="anonymous"></script>
<!--Popper JS-->
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js" integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
<!--latest Bootstrap 4 JS-->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js" integrity="sha384-h0AbiXch4ZDo7tp9hKZ4TsHbi047NrKGLO3SEJAg45jXxnGIfYzk4Si90RDIqNm1" crossorigin="anonymous"></script>
</body>
</html>
To work with responsive layouts based on CSS Flexbox requires access to a modern code editor like Dreamweaver CC 2018 -- the latest version. Or a comparable visual editor like Pinegrow.