Форуми / Cotonti / Extensions / Support / Use the contact form not only on standalone?

For first step try use read AJAX Helpers in Cotonti and in any tpl include html code an example:

        <div id="ajax_contact">
          <form action="index.php?e=contact" method="post" name="contact_ajax" id="contact_ajax" class="ajax post-ajax_contact">
          ...
          any your code from contact form
          ....
          <button type="submit" class="btn btn-primary">{PHP.L.Submit}</button>
          </form>
        <div>