End to end scenario

Hi,

I am working in SAP PI 7.1 now. Want to learn PO (PI7.4) ,

Pls guide me how to do end to end sceanrio in PO

and gone throught few docs about features , advantages  etc.,   Pls guide what we need to learn before that ?  Also what servers we should need to learn and practice (like NWDS, SAPNetweaver portal  and ECC)

Thanks in advance

Jeevitha N