When you first create your survey, we leave it in a "Paused" state. We do this in order to allow you to fine tune all aspects of your survey until you're ready to launch it on your website.
You can activate your survey one of three ways. The first is by clicking on "Activate this survey now" button on the "Preview" step while you're first creating the survey.
The second way is via the "Options button" on the dashboard. Click on the "Paused" icon next to the survey name and select the green dot next to "Enable".
The third option is available on the Targeting tab for each survey, in the right sidebar.
Once the survey is enabled, it will show to visitor when the targeting criteria is met.