What is the difference between liability vs uninsured motorist vs comprehensive coverage?

I'm 22 and don't have insurance, but I need a full coverage policy.

Liability is required by your state to legally drive on the road. Uninsured motorist coverage covers you and your passengers' medical bills if you are hit by another driver that does not have insurance. There is no such thing as "full coverage" but people normally use that term to describe comprehensive and collision. Collision covers damage to your vehicle if it is involved in an accident, and comprehensive covers anything else that might cause damage to your vehicle. I hope this helps!