Net-Map is a very flexible approach and there are a number of things (such as the concrete question, the kinds of links and the goals of actors) that have to be adapted for the use of the method to answer your specific question.
Now, how do you know, whether you have adapted it in the “right” way?
Well, there is no such thing as the one right way, but true enough, sometimes you will be able to adapt it in a way that serves your needs quite smoothly, while it might happen in other cases that you end up with more links than anyone could possibly process or that your research question confuses your interview partners because it is too broad or too narrow.
While pre-testing in the field is crucial to get to an appropriate procedure, I would propose a first step that happens in your office: Guide yourself through drawing a Net-Map, following the research question that you are planning to ask your interviewees. This is something you can do on your own, or, if you are working in a team, do it as a team exercise. Depending on your situation, it might also make sense, to draw a Net-Map together with the people who commissioned or initiated your activities.
This serves two different goals:
You will be able to understand, how far the procedure makes sense to you. Be attentive and look critically at any confusion, misunderstanding or uncomfortable feeling you have while mapping out the field you are going to work in and make sure to adapt your approach accordingly. If something annoys or confuses you, it will most likely trigger the same reaction in your interview partners.
Furthermore, mapping out this field will allow you (individually or as group) to assess your knowledge and knowledge gaps, your perception and expectations. It may guide you to prepare yourself better before going to the field. If working as a team, it will help you to benefit from each other’s knowledge and to avoid misunderstandings. And it will serve as an interesting point of reference after you have conducted your field work, as you will be able to see how your perceptions and knowledge changed through the research.