The document discusses different types of interviews, including structured, semi-structured, and unstructured interviews. It explains that an interview guide is used for unstructured interviews, containing a brief list of topics to be covered but allowing flexibility. When preparing an interview guide, questions should be ordered logically and use clear language. In-depth interviews are described as conversations with a purpose, where the researcher explores topics while respecting the participant's perspective. Strengths include obtaining large amounts of data quickly, while limitations include the personal interaction required and time needed for analysis.