hi,
for documentation, try the following options
- http://help.sap.com/s4hana. You should be able to find documentation about product features.
- www.service.sap.com/rds --> SAP S/4HANA -> SAP S/4HANA, On-Premise edition 1511 -> by download package, you find a bundle of SAP Best Practices documentation for process and configuration.
I am not aware of any Test System. But maybe others can contribute.
Best, Xiaohua