1)    To invite a project member to join your project, click the Project Members area on your project's home page.

2)    Next click the Add Project Member button in the top right.

3)    Then enter the new member's email and select their member role.  The last portion lets you select which areas of the project they can have access to.  Check or uncheck any areas you wish.  Then click Send Invite when you are finished.  The new project member will receive an invitation to join the project.