Extra class from rebirth how to get them ?

just bought rebirth and adventures but did not get the extra class, is there anything must do ?

 

There is no extra class, but rather two extra 'characters' or basically 'skins' for each class

For example, if you are a warrior without Rebirth, you only have two options, Male or Female.
If you have rebirth, you get two male options and two female options.