The tablet is simple and compacted with all the accessories you need, so you can start programming and making anywhere. SunFounder have many intuitive instruction books to guide beginners as well.
Raspberry Pi OS is a step-by-step guide that teaches how to create a simple operating system from scratch. The OS source code is largely based on Linux kernel, but it has very limited functionality and supports only Raspberry PI 3. The main goal is not only to teach OS development, but also to use the project as a starting point to learn Linux.