The full Raspberry Pi Workshop in step-by-step format can be found here https://core-electronics.com.au/tutorials/raspberry-pi-workshop-for-beginners.html
The shell is a program which processes our commands and returns outputs. We interact with the shell through a terminal. This could be an emulated terminal on the Pi's graphical desktop, or via remote connection for more advanced users. Getting comfortable with the shell is an important step, because it provides us with powerful tools to control how our Pi functions.
We're official retailers for Raspberry Pi in Australia - powered by makers, for makers! https://core-electronics.com.au/raspberry-pi.html