This article will explain how to add the feedback module on your InstantSite.
Scroll down to the Create your website section and click on the InstantSite icon.
Click on the Login button next to the relevant InstantSite package.
Click on the Edit link.
Click on the relevant page in the site map panel you want to add the Feedback module to.
Drag the Feedback module to where you would like it on your page.
This will display the Feedback module on your page.
For a guide on configuring your Feedback module please see: How do I setup the feedback module?