Hi Marie-Sophie,
the research method depends on your research question. These two are interrelated. For example if you want to know indepth knowledge regarding a subject methods like focus groups or interviews may be best. If it is something more numeric a survey may be suitable.
Try and read a lot around the subject, make questions, read and try and fine tune the question. Is there an area that is unanswered. Once you have the research question set the method.
But be aware: be realistic what method you use, what resources have you got? This may influence your question!