hi,
this is an overview of SAP LANDSCAPE
basically there are 3 clients :
1) development client : where we configure and develop objects using ABAP and customization etc
2) quality assurance client : where we can test the object and customization
3) production system : after development and Quality assurance, objects and customization will be transported to Production client (where end user work with it )only if objects and customization are providing desired business functionality.
hope this will help for basic understanding of SAP LANDSCAPE.
thanks