adding tooltip to toolbar icon

Dear Support,

on my prev. issue you helped us to setup an extra profile - icon into our toolbar (screeenshot). Now I tried to create a popup for the icon. These are the steps I did so far:
I went to the default.php into the folder: .../components/com_easysocial/themes/elegant/toolbar/default.php
and added this code:

<li>

				<a href="/<?php echo FRoute::profile();?>">

                		<i class="fa fa-user"></i>

                        <b><?php echo JText::_('COM_EASYSOCIAL_TOOLBAR_PROFILE');?></b>

				</a>

    	    </li>	

After I went to the language file into the folder: ...//language/de-DE/de-DE.com_easysocial.ini and added this line:

COM_EASYSOCIAL_TOOLBAR_PROFILE="Profil anzeigen"

I know I still missed at least one more step, in order to activate the tooltip. What would that be?

thank you in advance for your valuable time!

best regards!