A survey allows you to ask one question. Enter that question in the "Question" area.
Choose whether you want visitors to be able to answer it, or if they need to be registered on the site.
Add options for them to be able to select as answers in the "add option" area. Once you've added all of your potential answers, click the big "Add" button at the bottom to add the survey to your page.
Note: You can see the results of your survey in the Dashboard - just go to Dashboard > Reports > Surveys.