Scheduling in Order Management

Hi There

I am trying to get a very general understanding of how scheduling works in Oracle Order Management.   

My basic understanding is that at the order line level you need to specify a request date and schedule ship date as these are the attributes that determine what orders are selected during pick release. 

- What attributes are important to enter on the order line level in relation to scheduling?

- Are these attributes entered manually?

- I see references to something called ATP.  What is the purpose of this? What attributes are populated by ATP?

- What modules are required to implement ATP?  Is it Oracle Inventory, Oracle APS, Oracle ASCP?