First Helpdesk job. Need some help (I don't know anything)

I just got a help desk job and it seems like I can't ever help people. I mean, I know SOME stuff, but 85% of the problems I get, I can't solve. I have to get my co-worker to handle it.

Granted, this is my first Help Desk job and the guy working with me has 2 years here, but I feel like I'm not pulling my weight.

Is this normal? What should I do to become more helpful? Thanks.