To contact the buddies or the other participants of your language group, select the language group you’re attending under 'My groups'.
Right next to 'Sessions', select 'Conversation'. On that page, you can contact the buddies and participants in your language group -- you can read the posts already shared by them and reply, as well as write new posts.
Try to check this page often -- this is where the buddies will keep you updated on everything related to your language group.