How?
Follow the instructions in the video to HTTPS.
Why do I care if my Facebook account is secure?
To most of us, our Facebook is pretty much our most substantial presence on the internet. If anyone wanted to find out something about you, Facebook is pretty much the next place that someone would go right after they google your name.
Apart from the expected level of irritation from having to restore your account, you can also pretty much expect that you lose all your information, and receive a decent amount of damage to your personal reputation. Unless you don't really care about any of that, maybe you should spend the next five minutes to enable HTTPS.
Okay, fine.. so what is HTTPS anyway?
HTTPS is the most basic way of establishing a secure communication between you and the Facebook server. In WWII, armies use coded languages to communicate among themselves, ensuring that any enemies who picks up a stray message will not be able to understand it. HTTPS is the web-browser's way of talking in code, so that any bad guys picking up on the messages don't understand it. Geeks have fought a hard fight in obliging Facebook to enable this functionality, so please USE IT!