It's pretty easy to use, you just need a USB cable. But it is a cli like terminal so you do want to search for how to use it and not just guess because you can delete files accidentally easier. But you always just start with 'adb devices' and that just lets you know if it's working.

It's software that runs in the terminal. It just lets you pass on commands to your device that go beyond what the graphical interface can do (or allows you to do, really).