Need clarity around Project/Tasks

I am in need of a way to track/assign tasks for a project.  In Siebel, I know there is a project object and there is a relationship with Project Items.  I get that part, but it has been several years since I've worked with a client that used the project module.  What I'm struggling with is that in my previous usage of Projects, there was the ability to create an "MS Project-esque" plan with a list of tasks.  You could also load a "plan" that contained a list of tasks using a template or activity plan.  Those tasks could be