A Project Manager or PM is the person who is responsible for the planning and management of a building venture. Their scope covers everything from the initiation and project plans right through to the day-to-day management of the work. The PM will deal with costs of the project, the safety and all contractors working on the project.
Whenever there is a large quantity of complex work to be carried out a Project Manager will usually be hired to oversee and organise all aspects of the project. They will routinely work closely with the architects. Usually the architects design the work and hire the PM to carry out the construction. The PM will manage the construction team, plan the construction of the project, source the contractors and scheduling the scope of works. Ideally the PM and architects will work closely together during the project to ensure that the architects vision is executed correctly and ensure that any problems which arise are resolved.
You can post a job for a Project Manager on Service Central or use your existing connections ie by talking to your architect.