You must have a work permit to work in Turkey. Foreigners who want to work in Turkey must apply for residency within a month after they arrive in Turkey. You may apply for a work permit in Turkey or from your own country. The key point is, while applying for a work permit, you must be careful about the expiration date of your residency.
If your residence permit expires within a month, your work permit application might be rejected. After you prepare the required documents, you should submit them to Ministry of Labour and Social Security. When your work permit is approved, it is stamped on your passport. With your work permit, you will be able to work and run your business in Turkey.