IPhone 5, what does my limited warranty cover?

I have an iPhone 5, and the lock button doesn't work very well, and, I want to fix it. Does my limited one year warranty cover it? Can I fix it myself?

It covers everything except accidental damage like dropping it, or water damage. They will fix it or give you a new one on the spot, did it yesterday for my moms iPhone 4, the left earphone dosent work for any earphone.

Everything just dont do anything dumb