A ToolTip is what you see when you mouse over text or images that have been linked with a tooltip.  More info is placed in the pop up to explain the word(s) or Image(s) in greater detail.

To create a ToolTip, you first would select the text or image you wish to add the Tooltip to.

Then click on the "ToolTip" icon on the Toolbar.

Then type in the info you would like to use to explain the word or words that you are adding the tooltip to.

See how the tooltip looks on the website:

If you need assistance in getting a tooltip added please feel free to Contact Support.