I see people popping their necks... I have never popped my neck like them. Is it safe to pop the neck? If so how can I do so safely?

Probably. It's probably safe, but unnecessary. Some say it can lead to arthritis. I know of no studies that support this. If you want your neck cracked, go see a competent D.O. (doctor of osteopathy). Check the american academy of osteopathy to find a physician.
Safe but not good. It's 'safe' to pop your own neck, meaning you won't paralyze yourself, but it's not a great idea. Chronic cracking can eventually over-stretch ligaments leaving the joints susceptible to future injury or arthritis. The 'need' to pop the neck actually means there is a problem which needs to be fixed. Osteopathic manipulation can find and correct the root problem-which may not even be in the neck.