Well, this is the sub-forum for players specifically new to on-forum Diplomacy variants, but you're not far off. Normally, I think questions like this would go best in the PlayDip Academy sub-forum under the Players forum. (People periodically complain about the forum layout - I'm sure it will get tidied up eventually, but it is a volunteer-run site for the most part and there are always a thousand other things for the admins to take care of.)
Meantime, the option you're looking for is found like so:
Go to the home page (http://playdiplomacy.com). Once you're logged in, on the top right there are two buttons, "My Account" and "Log Out". If you go to "My Account", the profile page that comes up gives you a number of options - name, email, signature, time zone, and then a number of game options in italics. The first one of these, "Show territory / unit ownership details on hover", should be checked. (I'd recommend having it on for all games, especially if you've got units in the Balkans, but it's extremely helpful for Versailles.)