A short explanation for each project role.
Project managers have access to all functionality. Select this role for someone who should be able to change anything within the project. In most cases this is the leader or leaders of the project.
Supervisors have access to most of the functionality. Select this role for someone who will verify issues, tasks and checklists. This can be a foreman doing administrative work, or a supervisor in the field.
Clients can accept and reject change requests, create tasks, report issues and see almost everything going on in the project. Clients can not change anything regarding the project itself. Select this role for your clients. It could be couple building a home, someone refurbishing their kitchen or an entrepreneur interested in his construction project.
Contributors can be assigned tasks, upload documents, mark tasks as completed, and everything else that is needed to perform work at the construction site. This role should be assigned to those who are contributing at the construction site. Typically carpenters, plumbers, electricians.
Suppliers can be assigned tasks, upload photos, mark tasks as completed, and everything else that is needed to help with logistics, orders, and equipment. This role should be assigned to your suppliers.
Spectators can view the project, but they can not change anything within the project. This role should be assigned to those who wish to only view the project. This might be an interested party, a mother in law or an inspector.