Where to find planning, came from SOP or APO

Hello Friends,

I was just wondering where we find the planning data in PP, which is been planned in SOP or DP or APO.

Actually I want to know the cycle of data flow....

What is the kind of work, APO, DP and SOP user's do?

As much as I know, first DP user's forecast the demand then the data passed on to SOP, where we create whole sales plan and then the data flows to PP for manufacturing..... If I am right then what is the exact role of APO in this ???

And one more thing, where we find all this data in PP, in which T.Code ??

thanks sir.