You could fix it yourself, but I wouldn't recommend doing so, unless you actually know what you're doing throughout the whole process. I would take your car to a mechanic to have them identify the cause of the check engine light being on and have them repair whatever may be wrong; as there could be a numerous amount of reasons of why that came on.
Have you recently gotten gas? If so, open the gas cap, re-tighten it and then drive for approximately 50 miles. If the check engine light warning goes away after that process, that could have been what triggered it. If not, give your dealer, or your local mechanic, or whomever you trust with your vehicle needs a call and explain what is going on. They should be able to help diagnose what it may be, and if not over the phone, will be able to run a vehicle analysis to fix the problem when you bring to vehicle into them for service.