The document discusses the importance of researching the codes and conventions of documentaries. It states that understanding the codes and conventions is essential for determining which to include in one's own documentary. Different documentary types, such as mixed documentaries, incorporate specific conventions like interviews, voiceovers, and observations. By researching the conventions, documentarians can choose which to use depending on their chosen documentary type. The document also notes that conventions should be presented in an appealing way for the target audience, and provides examples of how conventions may differ based on whether the audience is younger or older.