When you place your mouse over the Voobly icon, user stats will be displayed - see the picture below:
You can choose ladder on the same AoC Profile page in your user control panel ("Get rating from ladder:"), while country is selectable in the "Settings" part of your AoCZone tab. If you, for some reason, don`t want your rating to be displayed in your profile, just check "Do not display rating in profile:" box.
(!) After applying any changes, don`t forget to click "Submit" button in the lower part of the page. For now, ratings/stats are refreshed once a day (per 24h).
Hope you like it
p.s. For detailed, step-by-step tutorial (with pictures), check this topic.