The basic article walks you through the process of figuring out your eligibility, based on your dates of service and so on. Just read through it to see in what category you may fit. It'll also suggest what to do next if you quality.
However, if you're not the sort of person that likes to read through a whole lot of verbiage, they offer an alternative: a pop-up calculator!
Click on the little picture of a calculator and it'll guide you through a series of question.
With luck, you'll be greeted with at the end with the message: