How to make link open in same window

Hi there, I’d like to make a link open in the same window. This is a button on the social button settings.
I see that you need to add “_self”, but I don’t know where to put that in to make the link open in the same window.

It is the topbar here: http://madamemayhem.com/

Thanks in advance.

https://wordpress.org/plugins/wp-topbar/