SAP MM program

Hi,

I am quite new to ABAP stuff (not used it since 2 yrs)

I want to write a program for MM tracking (Very New to MM module).

Right from Purchase Order to Invoice generation step and display it in alv.

I am aware of ALV programming quite well. but the problem is MM module. How to start is the problem.

I have to fetch data from PO ,PR,Costcenters for this , as well as GRN, Invoice data and display it on an ALV grid.