i am building a survey and I would like to have a few questions at the end only for a special group.
May I kindly ask you to please let me know how i Can find the section navigator?
The Section Navigator action is not part of the standard package for SurveyGizmo. You will have to contact SurveyGizmo Support and specifically request it for your account.
The Section Navigator is not standard because it is not easy to set up correctly. If you are not careful it can potentially damage a survey (ask me how I know). How do you plan to use Section navigator? Based on your first sentence I think that page logic might be a better choice for what you are trying to achieve.