The root account is an administrative account in Linux, that has absolute power over your system. Root can do literally anything, including destroying the whole installation.
root account is dangerous. Playing with root, even just for learning purposes, is not advised. If you absolutely have to try things with it, do it in a virtual machine, or on a throwaway system, you have installed for the purpose and has no physical access to your data.
Even a LiveCD won't be safe because with a root account you can easily mount your "proper" system and wreak havoc on your files. Just take
root seriously, OK? Promise?
There are two ways to gain
root privileges (also often referred to as "elevated privileges"): Via the built-in
root account, or the
sudo command. Both of these approaches have their benefits and drawbacks. Which you want to use is entirely up to you.