For a new product, bring a current process and a safe example of the information it uses. For an existing app, bring the same explanation alongside the available build and handover material. Your product owner should be able to describe the useful task in ordinary language, including what another colleague or system does after it.
The design review uses the actual kind of content people will enter or read. We discuss account roles, relevant device behaviour, corrections and any connection the task depends on. If offline work, notifications or another device function is required, its purpose and expected behaviour are agreed explicitly.
Backend and administration are part of that conversation. The proposal identifies what already exists, what the app is permitted to use and what new work is included. This helps reviewers judge the complete result rather than approve a screen whose receiving process remains undefined.