First, you should download the free 'Multiplayer Starter Pack' from the Xbox store. It contains a lot of valuable things including a free two-school arsenal that you can use to get this achievement.
Once you've downloaded the pack, simply go to Multiplayer Mode > Xbox Live > Lab > Edit Arsenal.
After that, select your arsenal and replace one of the Aura Particles with a skill that you've unlocked. Once you've done that, back out of the arsenal editor, save your changes and the achievement is yours!
EDIT: You can also unlock this achievement in the single player mode after you reach a certain point in Chapter 3.