The setting that controls when guests should see your feedback survey is located under Feedback > Settings:

The default setting is Show the survey form for rating 3 and below, which means that if a guest rates their stay as negative (1, 2, or 3), they will see your survey prior to being redirected to TripAdvisor. Guests who rate their stay as positive (4 and 5) will be immediately redirected to TripAdvisor.

You can change this setting as desired, or disable it completely, meaning that all guests will be redirected to leave a review on TripAdvisor.