If you want to display an informational page, when your respondents first visit your Survey you can use a Start page. Navigate to Surveys->Edit on the Survey you want to add the start page on. Click on the menu option “Create a start page for this Survey” and then enter your text in the dialog shown. If you want to deactivate your start page for this Survey, then you click on “Edit Start Page” option and choose “Do not use a start page”.
Please note: Once you have activated a Start Page, the menu option changes its name from “Create a start page for this Survey” to “Edit Start Page”.