I'm stuck trying to solve the problem below...

A test for Hepatitis C is given to a population of possible carriers. It is believed that only $10\%$ are positive. The test itself is only $95\%$ accurate for people who have Hepatitis C, and $80\%$ accurate for those who do not have the disease. What is the probability that a person has Hepatitis C given a positive result?

I know that I'm going to have to use Baye's theorem to solve it, but don't really know how?

If anybody could give me a hint, I'd be very grateful!