How do I assign a client to a project?

How do I assign a client to a project?

Do you have any tutorials that walk you through the common steps in setting up a project? Have spent the last 30 minutes trying to figure out how to do things like assign a client to a project, and set up completion dates for tasks and failing miserably, I feel like I have been shown the emperors wonderful new clothes but somehow can't see them. It just doesn't seem terribly intuitive to me, but I may just be showing my age ;0)

Thanks,
Nick.