When you've finished creating your survey, you'll probably want to run through it a couple of times to make sure it's all looking great.
To do this, you can click 'Preview' from the left hand menu when you're editing your survey.
The survey preview panel gives you a preview of exactly how your survey will look and feel to a user (with some small changes to make it easier for you to edit if you need to).
Any responses you put into the preview will not be shown on your survey report.
If you want to restart the preview so you can show it to a colleague, you can do that by clicking 'Restart preview' as outlined here: