Pay Rates are the amounts you pay resources for services. These rates are organized into tables, so you can pay different resources different amounts for the same service items by applying different pay rate tables.
Pay rate tables are further organized into Pay Rate Groups, groups of similar tables, so when billing you can search through a subset of your pay rate tables instead of the whole long list of tables. Set up groups first, then rate tables. Refer to the Rates setup workflow for the complete setup order.