We suggest the following approach to getting started with Inviwo.
If you have not, first take a look at the overview. Then download the Inviwo sourcecode and follow the build instructions. While compiling, go through the manual to see how the code is structured. After running and trying out Inviwo, implement your own super awesome algorithm or data importer by first creating a module and then creating a processor. Implementing your functionality in the process function of your newly created Processor. Lastly, detailed information can be found in the API documentation.