Project management is not a lot different to baking a cake.
PMBoK provides the fundamentals from which a recipe (a methodology) can be derived and thus the basis for blending the ingredients (inputs) from which the cake will be created.
Success will depend on the correct blending (logical and somewhat sequential integration of the requirements) and the heat in the oven (client time, cost, scope change demands).
We need to work as a team, so a blustering and aggressive non-consultative head cook (project manager) will be detrimental to a coordinated effort. For more complex menus, a master chef (project director) may be required.
Too many cooks (human resources) can spoil the mix, as can too few, so we need to secure the right resources with the appropriate competencies for the type of cake we intend to bake. Each needs to know their role and contribution to avoid confusion in a small workspace.
The ingredients must be available when required so a buying strategy (procurement) is important early in the preparation cycle. The ingredients should be prepared and be available as required by the head cook and the team.
If the oven is gas-fired, then keep a spare gas bottle handy as nothing ruins a cake faster than a lack a of awareness of risks and the failure to apply appropriate mitigation strategies.
In addition we need to keep a close watch on the time allowed for putting it all together and baking (the schedule). The cooks may have other commitments or priorities!
Of course at the end of the day we can bake a beautiful cake that tastes lousy, thus the business outcome evaluation (eating and enjoying), as distinct from project outcome, (how well we achieved time/cost results) is probably the most important consideration.