Add a new question by clicking on "Add item" at the bottom of your page.
You are ready now to select the item you need to add to your survey:
To know more about the different available items: Click here
In your Survey, just click on a question to modify it. Doing this, you can configure all the settings on this question.
Don't forget to click on Validate when your question is ready.
To finish, click on Save when your survey is.