Have you created a Survey for your course? Add this Survey to a (sub)module on the course Content page to make it easyly accessible for students.  

• Click Content in the navbar of your course.
• Go to the relevant (sub)module to which you want to add the survey.
• Click on Add existing in the upper right corner.

• Click on More, a new window will automatically open. 
• Scroll down the window and select Surveys.  Select the desired survey in the list.

You have now added the survey to the (sub)module.

• Click on Open Survey to edit it.