How to add a sub tag under a primary tag like your site

Hi, how to add a sub tag under a primary tag like your site? It seems that all my tags are on same level. Does it require any extension?

Clifford9547 just drag it a little to the right, between two primary tags:

It has to be a primary tag too

robinodds It doesn't have to be a primary tag. It can be a secondary tag as well.

tanks guys, I have figured it out.