You are viewing version 3 of the library, the latest version is
<!-- display above the button -->
<button type="button" class="btn btn-primary" data-toggle="tooltip" data-placement="top" title="Tooltip bovenkant">
    Bovenkant
</button>

<!-- display on the right the button -->
<button type="button" class="btn btn-primary" data-toggle="tooltip" data-placement="right" title="Tooltip rechterkant">
    Rechterkant
</button>

<!-- display underneath the button -->
<button type="button" class="btn btn-primary" data-toggle="tooltip" data-placement="bottom" title="Tooltip onderkant">
    Onderkant
</button>

<!-- display on the left the button -->
<button type="button" class="btn btn-primary" data-toggle="tooltip" data-placement="left" title="Tooltip linkerkant">
    Linkerkant
</button>

Tooltips

Based on the version from MDB:
https://mdbootstrap.com/javascript/tooltips/