please explan step by step

Hi Experts,

I have an requirement , i have to fectch the data from SAP tables ( ECC6.0) MARA, MARC and MAKT ( using join) and sent system B ( the user will request by entering MATNR and WERKS through web ) through sap XI

as per my understanding i need to use SOAP and ABAP proxy, can you please explain in details

1) it is request and response how soap will consume the request and sent the resp[onse?

2) in Proxy ..where the abap logic needs to be write in the FM inside Class or ABAP editor ?

..i have gone throgh the links in SDN ..but for my requirements i need the step by step explanation

Regards

Neeru