The best way to do project management in SAP is to not do it in SAP.
General
SAP Project System (PS) is a part of SAPs Project and Portfolio Management tool that helps manage the execution side of projects.
SAP PPM (Portfolio and Project Management) is the solution offering from SAP that supports the planning and execution of projects and portfolios of projects.
The PMO (Project Management Office) is the department within a company or organization that sets the guidelines and success metrics for project management.