Need Help to Understand SRM Organization Structure

Hello, Can anyone give me resources to learn more about SRM organization? I'm currently at a sandbox enviornment to prepare for a project and wanted to play around.

Problem is i don't understand what is what. Business partner means what? Do I control all authorization in SRM through the organization structure? What is a position, and what is a role? How can you link your SRM purchase organization with ERP purchase organization etc.

I really need the concept as it is different from how the organization structure is in R3.

Thanks and Regards,

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