1. Go buy this:
2. Follow these instructions:
That will give you the fault code(s) that is behind your CEL. Cross-reference it to the table of fault codes at that URL and go from there.
Your black and white terminals on the car for doing this are located above the fuse box. Remove the fuse box cover/storage bin (by your left knee in the driver's seat) and look up under there and you'll see them.