In National Quest, how does a person get Alliance cards?

Alliance cards will unlock as you level up and earn more points.

Every time you do a quest you will earn class Exp. If you go to the Class Manual option in the Class Hall then you will see your level at the top and an Exp progress bar. When you reach each new level you will gain Class points to use unlocking cards. With each level you will need more Exp to reach it.

Once cards are unlocked you can then go to the 'Card Use' tab and select which cards you want to activate. You cannot use them all unfortunately. Make sure you activate any card you have the give you a boost to your Exp so that you can level up faster.