I am trying to setup MRP, But the Planning Categories, Planning Groups, Planning Rules & Supply Plan Definition. These new settings are very confusing.

• Planning Categories - Groups of items that are planned in a similar manner. For example: Accessories, Consumables, Commodities, Other Raw Materials, Vendor XYZ Item, etc. • Planning Item Group - An additional hierarchy similar to categories that allows you to add Categories and individual Items (ex. Materials, Semifinished goods, Finished Goods) • Planning Rules - Allows you to add the hierarchies above or items to define typical movement of product (don't set up everything here, only concrete rules like "this category is always sourced from location A to location B and takes 7 days transit time") • SP Definition - Scope of the current planning workbench including how you consider demand, what rule group should be considered, what saved search drives your view of items, how far out you're looking and what group