Proof beats polish
Your submission should prove that a user can understand and use the app. Do not only say what the app does. Show the screens and states that make it usable.
What to submit
Pick at least 3 working screens or flows from your project. A flow can be login to dashboard, search to results, or add item to confirmation.
Each chosen screen should show the design work from this track: hierarchy, spacing, readable type, contrast, empty or error states, and clear UI copy.