How to sell a cryptocurrency call option

A call option is an agreement that gives the option buyer the right, but not the obligation, to buy a specified amount of cryptocurrency at a specified price within a specific time period.

To learn more, read the Wikipedia article about call options, or the Investopedia call option entry.
Step 1
Register an account with AgoraDesk. You get a free and secure online cryptocurrency wallet. No additional apps are needed. If you already have an account, skip to the next step.
Step 2
Go to the main page. On the top bar of the website, select 'Trade options'. Then, select the cryptocurrency you want to trade by pressing the corresponding tab on the row above the ads table. For this example we'll choose BTC. To the left of the cryptocurrency selector you should select 'Call' options. In the left column you should then select the 'Sell' tab. If you wish to change the country,currency, payment method or specify the needed amount, click on the 'Show search menu' button, choose the desired parameters, and press the search button. If you're unsure how you want to be paid, choose 'All online offers' as your payment method. The site will list traders available in your region.
Step 3
From the list of advertisements, choose one from a trader with a good reputation score and a high amount of trades. A green circle means the trader has been online today, a yellow circle means they have visited the site this week and a grey circle means that the trader hasn't been here for over a week. You can click the 'Sell' button to view more information about an advertisement.
Some payment methods are considered high-risk. Cryptocurrency transactions are completely irreversible. Once you sell your cryptocurrency it's not possible for you to recover them, even if the payment is reversed. That's why we recommend you sell with a low-risk payment method to experienced users with a large amount of previous trades and 100% feedback.
Step 4
After you press the 'Sell' button you'll see more information about the advertisement, including the terms of the trade. Read through them before submitting the trade request, if you don't agree with them you can go back to the previous page and choose another advertisement. To start the trade, type in the notional value or the underlying BTC amount of the option and click the 'Send trade request' button to start the trade. Once you start the trade, the underlying BTC plus the 1% AgoraDesk fee will be moved from your wallet to the trade escrow.
Step 5
Once you've started the trade, on your right side you'll see the section that'll guide you through the trade's flow. The first thing that happens when you sell a call option, is that the buyer needs to pay you the premium using the trade's payment method in the amount displayed on the trade page. If they fail to complete the payment within the payment window, you'll be able to cancel the trade. Once the buyer completes the payment, make sure you've received it before pressing the 'Confirm payment' button. Never confirm the payment, unless you are 100% sure you've received it - there have been scammers who try to trick sellers into prematurely confirming the payment.
Step 6
Once you've confirmed the payment, the option contract will activate. To your right you'll see a countdown timer that'll show you when the option expires. Should the option expire, you'll receive the underlying coins back and keep the premium.
Step 7
If the buyer decides to exercise the option, they'll receive a portion of the underlying asset equivalent to the difference between the notional value and the current market value of the underlying. The rest of the underlying will be returned to you.

In some cases, the buyer might want to exercise the option with gross settlement, where they will have to make the payment for the full notional amount of the trade. The same rules apply here as with the premium payment - never release, until you've made absolutely sure that you've received the payment. Once you press the 'Release' button, your coins will be transferred to the buyer - which will conclude the trade.