This work presents an authoring tool for supporting the creation of immersive instructions for industrial processes. Our system simplifies the creation of instructional content by providing an immersive virtual reality environment that enables expert operators to interact directly with virtual replicas of industrial devices. Hand movements, tool usage, gaze, spoken comments, and machine part movement are recorded using a head-mounted display. Editing of instructions in virtual reality is aided by automatic segmentation of recorded data into individual steps and visualizations of regions with intensive activity. A qualitative evaluation of our system by industrial experts shows that it is a viable alternative to current practices in authoring instructions for assembly and maintenance.