generar un boton flotante

<div class="fixed-action-btn">
  <a class="btn-floating btn-large red">
    <i class="large material-icons">add</i>
  </a>
  <ul>
    <li><a class="btn-floating red"><i class="material-icons">insert_chart</i></a></li>
    <li><a class="btn-floating yellow darken-1"><i class="material-icons">format_quote</i></a></li>
    <li><a class="btn-floating green"><i class="material-icons">publish</i></a></li>
    <li><a class="btn-floating blue"><i class="material-icons">attach_file</i></a></li>
  </ul>
</div>