You asked, “What are the roles of guidance and counselors in schools?”
If we are talking about public schools, the roles are to keep the students informed of their academic progress. You know, “You want this level of diploma and you need to take these classes to earn that diploma.” Most believe that the counselors are there to provide personal growth counseling, but that is not the job of the academic counselor; though many believe such and some take a stab at such with distraught students.
In short, the counselors are to say, “Here is what is offered” and “Here is what you need to take to get the level of diploma that you want.” That’s it.
If you want to know what it is like to be a nurse, talk with a nurse. If you want to know what it is like to be an engineer, talk with an engineer. Academic counselors are of very little help with these sorts of things; it is simply not their job. You would not ask a welder what sort of food to eat for a well-balanced diet, would you?