As you have prepared to be in Korea, I’m pretty sure you registered for visa(D-2-6) before arrival. To make your stay legal, you need one more step: Bringing documents to the local Korean Embassy and apply for visa.
What are the documents? There are mostly 3.
- Certificate of Admission
- Letter of Acceptance
- Certificate of Business Registration of your Korean School
Additional documents may be required depending on your place of stay. Please contact Korean Embassy around you for detail.
Good luck on your Korean stay!:)
Your friend, Shai