There are multiple functions for this template. There is the standard hover-over text, the tabber without default open tab, and the tabber with default open tab. For the tabber use, it is advised to use it on a new text rule.

Hover-over text

If you want to use the hover-over text function instead of using tabs, use the following:

{{Tabber|tabs=no|text that always appears|text that appears at hovering}}

That will result in: text that always appearstext that appears at hovering.
To insert enters, use <br/>, or add |div=div to the template. The latter method is also needed for lists.

Tabber with default open tab

If you want to have a tabber with a default open tab(the first tab), use the following:

{{Tabber
|t1=title of tab 1
|t2=title of tab 2
|t3=etc...
|t4=title of tab 4
|c1=content of tab 1(default opened)
|c2=content of tab 2
|c3=etc...
|c4=content of tab 4
}}

This will result in: