What are KVM switch & extender, how to use them?

What are KVM switch & extender, how to use them?

Alex recently came across the term "KVM" while trying to figure out how to use multiple computer setups with just one monitor, one keyboard and a mouse, or instantly switch between these computers from time to time without any hassle, then Alex found Kinan on the internet, and decided to reach us out to learn more about KVM...