Metal detecting is not a game. Therefore, it has no rules. It is necessary to purchase or borrow a metal detector. Then take it to somewhere like a park or, even better, a beach, preferably after a storm, and turn it on and start scanning. You may find nothing at all; you may find a cigarette lighter or a coin; or you may find Blackbeard's treasure. Some people in good locations make a fairly good second income from metal detecting, but most places aren't very good.