I am using a custom template and just added:

<span class="custom-tooltip">    <a href="#" class="tooltip-toggle">Test ?</a>    <span class="tooltip-content">Tolltip description come here</span></span>

and than added below style code in my theme styles-l.css

.custom-tooltip {    .lib-tooltip(right);}

and run command below
bin/magento setup:upgrade