 you want to install</li>
</ul>
<p><img src="../../img/manage-extensions-dialog.png" alt="Image Alt"></p>
<ul>
<li>click on the <em>Add</em> button,</li>
<li>you will see a message that tells that the extension is installed</li>
</ul>
<p><img src="../../img/manage-extensions-extension-installed.png" alt="Image Alt"></p>
<ul>
<li>a new icon appears on the left toolbar,</li>
<li>click on it,</li>
</ul>
<p><img src="../../img/manage-extensions-create-a-model.png" alt="Image Alt"></p>
<ul>
<li>you can now use t