As its name implies, this section covers the physical nuts and bolts of computing, including changes to the platform itself. From simple upgrades, like adding more memory, DVD players, or hard drives to actually building your own computer. It has close links with the installation of an Operating System (OS) when you need to know the configuration of the platform the OS is going to run on. Maybe you want to run two different operating systems side by side, (dual or multi boot) in which case you will probably need to become familiar with disk partitioning.
At a more fundamental level is this question How do computers work?. The Raspberry Pi (a low cost computer motherboard) is one way to make the inner workings more accessible. People are encouraged to add peripheral devices, which in turn need to be programmed to talk to the motherboard. The board has also been used as an interface in robotic projects, to add movement to say a Turtle graphics program.
The Raspberry Pi software includes an app called SmartSim. This is a emulator for an electronic (digital) circuit. This enables circuits to be tested, before they are actually built.
Before making any changes to your computer, its essential you backup your data, because some of the the changes may be irreversible. While Linux can be installed alongside other operating systems, more or less automatically these days, it is still a good idea to have some appreciation of what is going on in the background, and the compromises being made, e.g. in terms of disk space allocated to each system.
Can data be transferred to Linux from my current operating system? In the majority of cases the answer is yes, but applications cannot be transferred. Some commercial software providers still present obstacles to the free transfer of data, thus locking you in to that particular vendor.