Well. It easy. A bit.
Well one you enchantment your weapon. ( sword,axe,and etc )
It use 1 LEVEL. And to see your exp bar you must have 1.0.0 version up.
To see. And to get more exp go kill some pigs or those creeps. ( EVEN ANIMAL ANY TYPE OF ANIMAL )
And if you want more exp insane. Go use NBT Edit it like you are using cheat. In minecraft.
I will put the link of video down to this post.