This part of the developers guide describes how to build any of the sister projects from source, for example, just to get a better understanding of how the project works, or because your organization requires any open source projects to be re-built in-house.
This part of the guide also describes the prerequisite software that needs to be installed prior to building from source.
If you are looking to contribute to any of the sister projects, the steps in this part of the guide also apply, but see also Part II, “Contributing Changes” for additional steps.