If you want to add custom icons to cells. please, add this code to your page via text editor:
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" type="text/css" media="all">
This code enabled using of fontawesome on required page (post). List of available icons you can find here: http://fontawesome.io/icons/
From this moment you can add code for any required icon to the table cell and it will be shown on the frontend.
If you want to add tooltip to an icon, you should extend it’s code to something like this: <i class=”fa fa-cog” title=”Do you like my fa-coq icon?”></i>, where title=”Do you like my fa-coq icon?” is your tooltip text for icon.