A first version that tries to be the whole company will not teach you whether the main job works. Pick one person, one task, and a finish line you can see.
For a walking club, the one job is: find a sample walk and save it. Maps, payments, and memberships wait. If the saved favourite works, you have learned something. If the page also processes money, you have learned less about the favourite and more about a payment provider.
Write the finish line in the request: “This first version is done when a member can browse sample walks, open one, and save a favourite on the device.”
BitBytec desk. This is an explanation, not a recorded build. How the product is meant to work.