It would be pretty obvious to most working project managers: a project starts with a business need; or a 'mission' if you like that kinda language.
The impluse of some is to rush to a scheduling package and start making up dates for actions that they think will progress the project to an end result.
Not so fast: a lot hangs of the mission that needs to be developed before one can understand the components of the project to achieve the mission and deliver a business benefit.
The most important item that develops from the mission is the description of the technical performance required (what will the project's deliverable do) and the criteria by which one would know that the required performance has been achieved. Only then can one develop the project components, create a work breakdown structure, analyse that into activities and produce a schedule.
But there's something prior to these details.
For a project manager to deliver a project he needs to establish the capabilities needed to create the deliverables. This goes hand in hand with developing the WBS and possibly comes before the budget. Development of the budget comes from an interplay between capability, technical performance it can produce, schedule and business benefits. The PM has to have a bright eye to trade-offs and how value can be created and delivered by the project.