Hi,
Below are the steps for defining busines partner
>Business Partner Number Ranges
IMG->Business Partner->Relevant Settings for Business Partner->Number Ranges->Business Partner Number Ranges
>Define Groupings and Assigning Number Ranges
IMG->Business Partner->Relevant Settings for Business Partner->Number Ranges->Define Groupings
>Assigning Account Group to Vendor
IMG->Business Partner->Business Partner Vendor->Number Assignment: Assign Account Group to Vendor
>Vendor Roles
IMG->Business Partner->Business Partner Vendor->Vendor Roles
>BP Role
Comes predefined TR0150 for Issuer
You can do business partner integration with customers as well. check Business Partner Creation Error
Hope that helps
Regards,
Jyoti