<!DOCTYPE html>
<html lang="{{ page.lang | default: site.lang | default: "en" }}">

  {% include head.html %}

  <body>

    {% include header.html %}

    <main class="page-content" aria-label="Content">
      <div class="wrapper">
        {{ content }}
      </div>
    </main>

    {% include footer.html %}

    <!-- jQuery -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <!-- Bootstrap -->
    <script src="../assets/bootstrap/js/bootstrap.min.js"></script>
  </body>

</html>

<!DOCTYPE html>
<html lang="{{ page.lang | default: site.lang | default: "en" }}">

  {% include head.html %}

  <body>

    {% include header.html %}

    <main class="page-content" aria-label="Content">
      <div class="wrapper">
        {{ content }}
      </div>
    </main>

    {% include footer.html %}

    <!-- jQuery -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <!-- Bootstrap -->
    <script src="../assets/bootstrap/js/bootstrap.min.js"></script>
    <!-- JS -->
    <script src="../assets/js/main.js"></script>
  </body>

</html>

Add script linking to the main JS file
Add script linking to the main JS file
