You need to a linked GW1 account and access to the HoM.
First You any armor packed into inventory
Second Travels to the HoM
Third Speak with Kimmes give the historian and let you match the wrapped piece of armor the corresponding skin.
4th Transmuted this skin now often on the armor piece and you will receive for each 10 Transmutierungen (you can download Java word?) Achievement points.
5th Repeated the whole thing as long as you want.
have fun!
(found this on an other forum... just would share it with u... translate by google.)