You can talk to a confidential advisor for advice and support whenever you have to deal with unacceptable behaviour, like intimidation, (sexual) harassment, aggression, violence, discrimination, bullying or stalking, or when faced with a conflict in your work situation connected to such behaviour.
In addition, you can lodge a formal complaint with the Executive Board. Such a complaint should always concern a particular action. Such actions may be unacceptable behaviour as detailed in the above, but may also be other forms of improper conduct by a staff member, by a university body or administrative authority, or by the University of Twente in general.
A complaints procedure is all about a behaviour. An objections procedure, on the other hand, is about decisions with consequences for one's legal status. You may appeal the Executive Board's decision in court.