BPM Scenario

Hi All

I need to use BPM in one of my current scenario.

<b>FIRST STEP</b>

Legacy File(MQ Series)-------> SAP XI(Validation)

<------ Back to legacy if Error

<b>SECOND STEP</b>

SAP XI(Via Proxy) -

> SAP R/3(Validation on Data)

<----

Back to XI with validated Data

<b>THIRD STEP</b>

SAP XI(Validated Data Posted via IDOC) -

> SAP R/3

This being my first object in BPM, kindly suggest me some tutorial in this regard for developing BPM. Which Msg Interface will be Abstract and what are containers and Objects will be used(Switches) and how to do exactly the configuration in IR and ID.

Best Regards

Swetank