How do you join a party on stardoll?

Click on the 'Chat' tab on the top bar of stardoll. And click a chatroom you'd like to join. A chat/party has a maximum limit of people allowed so you may get turned away if there's a lot of doll sin there already, but most chatrooms are not full. You can play games in there (but only the host/owner can choose to do that). You can also choose a different country and attend a chatroom there - that way you can meet people from all over the world. Hope I helped :)