Chris is telling you to look into the XenForo ACP and use the basics of the Facebook integration code there (for the option) to learn how to accomplish what you want. You will need to be in debug mode.
The system isn't design to have two separate options together completely as you want. Any type of CSS solution would require it to be the same option. Open up Chrome's element inspector and start messing with CSS. Its the best way to learn.
He is using a custom display, with custom backend handling (to store the option) and each one that is displayed on the same line is within the same option.