Fixed left sidebar

You can activate fixed position option to the left sidebar element by adding this class (be-fixed-sidebar) to the main wrapper (be-wrapper) element this way your main structure should be like this:

<html lang="en">
  <body>
    <div class="be-wrapper be-fixed-sidebar">
      <nav class="navbar navbar-default navbar-fixed-top be-top-header">
        <!-- Top bar -->
      </nav>
      <div class="be-left-sidebar">
        <!-- Left sidebar -->
      </div>
      <div class="be-content">
        <!-- Main content -->
      </div>
      <div class="be-right-sidebar">
        <!-- Right sidebar -->
      </div>
    </div> 
  </body>
</html>