The information what you need to use Design Studio including the SDK can be found on many places. My problem was there is no guide where you find everything and here is a list:
- Download the newest version of Design Studio
- Download Eclipse IDE for Java EE Developers
- Download Design Studio SDK
The actual developer guide can be found here: http://help.sap.com/boad
Note: Download always the same version (If Design Studio 64Bit, then also Eclispe 64Bit). If the architecture isn't the same, you can't develop with the SDK.