SAP APO Installation

I am trying to install SAP SCM system and need some help...

1. what is the difference in SAP SCM and SAP APO ?

2. Where can I get the downloads from market place and which files will I need to install ? Can you guide me to the path under /swdc ?

3. Where can I get the related installation guide on SAP APO and Live Cache... ?

4. Is there any specific thing that I need to download to ensure that following business processes are covered ?

Demand planning & forecasting / vendor management inventory

PS: This is on Win 2K3 Server and Oracle 10.

Thanks,