Where to go from here
You can learn almost everything about REBOUND by looking at some of the example problems.
If you have downloaded the source code of REBOUND, then the C examples are located in the examples/ directory.
The python and iPython examples are located in the python_examples/ and ipython_examples/ directories respectively.
You might also want to have a look at the rebound.h file in the src/ directory which contains the precise function prototypes and structure definitions.
The user interface and basic concepts and conventions used within REBOUND are described in the API section of this documentation.
If you run into a problem or can't find an answer in this documentation, open an issue on GitHub or e-mail one of the contributors. We'll do our best to help you quickly.