What is the Role of SAP PI in SAP SRM?

Hello Gurus

I'm from SAP-XI background.

In my project I need to create a scenario from SRM ---> PI/XI ---> MDM.

I'm having the below queries regarding this scenario.

1) Do I need to download the "XI CONTENT for SRM SERVER and import it into PI server.

2) If so what is the exact location in the service market place from which I can download

3) What are the steps that need to be done between SRM and PI and also in SLD so that data will be sent from SRM to PI.

Can anyone answer my queries.

Thanks and Regards,

Pruthvi