Presented is a literature study into the importance of how information in assembly instructions in manual assembly is presented, more specifically how various factors such as the complexity of the assembly itself, the mental and physical workload of the worker, as well as the experience and skill level of the worker affect the requirements for information presentation. The requirements made by Industry 4.0 on flexibility in production lines and an increased number of variants produced causes increased demands on workers, which leads to more cognitive demands being made on assembly workers. Studies exist around assembly instruction modes, but have in many cases ignored factors such as worker skill level, mental workload, and task complexity and how these affect the requirements for information presentation, which is a major contribution of this study. The findings are that no single solution fits all requirements, but that the aforementioned factors should be taken into account.