Spark and Phone Plugin

Hi,

I just installed Spark 2.7.7 and Openfire 4.0.2.  Spark shows a Phone plug-in and I enabled the SIP Phone Plugin on the server.  But I don't see any options for configuring this on the client side or making calls.  How do I use that?

Also, is there a way to change the font size used for the main window, menus and contact list?