This page explains how to add a TripAdvisor Review widget to the booking page
1. Copy the widget code from your TripAdvisor account.
2. Add the code to your booking page
You can add the code snippet into and editable field on the booking page. Click on "Edit" then in the editor on "Source" to insert the code into your booking pages source code.
If you are using the responsive booking page make sure the module which you want to use is activated. Use this help page if you need more information on how to manage modules.