Hey @AhmetBurakS872, if google translate worked properly, I understand you're trying to remove your free lecture preview.
Please keep in mind you need to select enough lectures totaling 10 minutes of video content, including the first video lecture. This can't be enabled. Your first video lecture will automatically be available for the free preview to ensure there is always content available for students to view.
You can learn more about it in this support article. If you still have issues, feel free to reach out to instructorsupport@udemy.com. The team will be happy to help!
Abbie Reyes
Udemy Community Team
