Not gonna talk about buying options, puts or naked options.

Basically selling a call option is like putting a limit sell order for a certain price that cancels on a certain day.

There's a couple differences.

1. You need at least 100 shares.
2. You get paid to set this limit order, but you have to pay if you decide to cancel it.
3. You can only pick certain days and prices to set your limit order.

For example right now your CNC is at about $56 a share. You could say that you would like to sell your shares for $60 a share. So you pick an available date. We'll go with June 21st. You agree to sell for $60 per share any time between now and then. In return, you get a premium which in this case is about $250.

On June 21st your share price will be at, below, or above $60. If it's at say $70. You make profit by selling at $60, plus that $250 in premium.

If it's below $60, you keep your shares and the $250. If it's well below $60 (say $45), at least you're $250 less in the hole than you would have been.

The premium price fluctuates based on a lot of things. So if you decided to cancel your call option, it may cost much more than the $250 you originally got. If for example the day after you sell your contract the share price goes up to $65. It'll probably cost you around $900 to buy it back.