Usually the first step in implementing Oracle apps HRMS core is to define the Business group
 
What is Business Group:

In business :

The  business group  is most commonly a legal entity that is a type of conglomerate or holding company consisting of a parent company and subsidiaries. Typical examples are Adidas Group or Icelandair Group.

 
In oracle apps:

The largest organizational unit you set up in Oracle HRMS to represent your enterprise as an employer is the Business Group. A Business Group may correspond to a company or corporation, or in large enterprises, to a holding or parent company or corporation.
 

To define a business group we need to do the following:

  1. Enable the Currency
  2. Defining business group