Senior projects vary from semester to semester, depending somewhat on the professor in charge.
The basic intent to have you propose, implement and then finish a software related problem. This may not seem very different, but most students move on to other problems the moment anything begins to work. In this case you are to finish, polish and then provide proper documenting. You will work on this problem independent of the manager, but in close contact with the client. There will be several deadlines that must be met, some imposed by the client, some by your manager.