Distributions
The kiOS "core" project is predominantly focused on compiling the base kiOS system, including kiOS-specific code and third party required binaries, and bundling this as a standalone EFI binary.
The kiOS project maintains documentation on various ways to install this EFI and setup the system, however it attempts to be reasonably unopinionated and platform agnostic.
Bundled Distributions
Clearly, for convenience, there are a few scenarios in which a complete "out of the box" experience is more desirable (most notably for cloud installations, or hobbiest bare-metal setups).
AWS
The kios-aws project contains code relating to the specific bootstrapping steps involved when running in AWS.
This project also builds and maintains a set of public AWS AMI Images in each AWS region.
Raspberry Pi
Danger
This project is not currently maintained - a lot has changed in kiOS since this project was last supported, so there are likely to be a number of issues.
There is also some support for the raspberry pi 4. Currently, these files live in the kiOS core project, however the aim is to move this out to a separate project at some point.