Budget - the resources demanded by our workplan. It is usually necessary to iterate through these five scoping layers until we get a supportable business case. Resources are deployed to a workplan. The workplan is executed. Outputs are produced and delivered to customers.
Customers utilise outputs and, as a by-product, generate our target outcomes.
Basically the same scoping procedure should be employed, but here, of course, we know in advance the size of the available budget. When we iterate amongst the five scoping layers, we seek a supportable business case for a project that meets the budget constraint. Keep paring down outputs. Make corresponding reductions in the scope of work. Check to see if the budget constraint has been met.