How do you level up here?

I just wanted to know how you would go about leveling up, I've answered plenty of questions but I only see level 1 by my name. So how do I level up? I would search it up for my self but I'm going to listen to my Tim and Sid Uncut podcast on my Xbox 360 since my Ipod Nano cord isnt connecting to my itunes so I can't download it to my Ipod.