The Design Document tells the story of your design. Where are you in the design process, and how did you get here?
The audience is both design reviewers and future EPICS teams who need to continue the design or maintain the project after it has been delivered. Think about what you would need to know if someone was giving this project to you.
The design document is a living document that is updated throughout the project, not just in time for design review.
The document should include a project description, project specifications, significant design decisions, diagrams of final project implementation, bill of materials, assembly information, and maintenance information.