MS Word - Setting period leader in 'Tabs'

In Microsoft Word,

Under Format -> Paragraph -> Tabs... I am trying to set the 'Leader' to "2......" in order to insert periods when I hit the tab button. When I am doing this in my current file, the buttons are grayed-out.

I am creating a wedding program and want to fill the space between names and descriptions with periods, i.e.

"Name.......................................Friend"

Any suggestions? It seems this may not be the best way for me to fill with periods evenly. Ideally I would like to fully justify the paragraph and insert periods for any space between entries.

Thanks in advance.