Can I take GCSE exams if I was abroad and didn't take year 11 in an English school. If not what should I do?

I am in Turkey an I will be moving to Derby soon. I am 16 years old and I want to take GCSEs but there are a lot of complications. I have not done year 11 and my GCSE exams. I haven't done any coursework either. Basicly I wasn't in England from year 6 to 11 how can I take GCSEs please I'm beging you for help me!