Help on incoming Idoc's

Hello All,

I am new to SAP Interface and looking answers to my these below listed questions.

Scenario: Need to implement an interface that should trigger an idoc to sap system through which as SO will be created.

--> XYZ company will get a input file from some middleware and using that input data it will create an outbound idoc and sends to our system.

I guess this will be an incoming idoc for me.

Now after this what i need to do?

Do i have to do any settings in my system?

Do i have to create any program, FM to process this incoming idoc?

What will be my job?

Do i have to do field mapping? if yes how to do?

Please answer these points in detail, if possible explain me using transaction codes.....

Thanks in advance for your earliest reply.

Regards,

Devasing.