Direct answer

The practical whole-house model

Start with one room-by-room schedule and separate fixed building materials, custom joinery, loose furniture and FF&E, lighting and hardware, soft furnishings, logistics, and local installation. Give every item or package a stable code, specification status, quantity basis, budget state, supplier state, approval state, and destination responsibility.

Use specialist suppliers where their category is stronger, but maintain one procurement register across them. Budget models can help test feasibility, yet every real order must be recalculated from drawings, quantities, destination, packing data, freight, duty and tax, delivery access, installation, defects, and reserve.