You can tell which armatars require the number of points by looking inside the control panel. In the same way you got your dwarf armatar, you can scroll downward to see empty squares. These have numbers below them, showing how much AP you need before you can choose them. So once you get enough, say 250AP for one set, they will appear in your armatar slots.
Ur not actually supposed to tell when u get them.... If u knew u would pass out, it's a lot. It took me about a year to get this one. A whole year.....