Stop orders are submitted on the opposite side of the market and are traditionally protect a position. A buy stop order is submitted at a price higher than the current best bid but does not fill until that price trades. A sell stop order is submitted at a price lower than the current best offer price.
Note that if the market is moving rapidly you may get filled at a worse price than the one you entered. If you want to prevent this by setting a limit price for the stop then you can do so with the Stop limit order type.
Stops are useful as loss limits as you can use them to close out a position automatically if the market goes against you.
When submitting an order into the chart you there are different prompts you can enable. For this example we went to the Tap2Trade Properties and set the order confirmation to order ticket. We we tapped in the sell column and below is how the order ticket looks. We set the price for 21170 and then clicked submit. The order ticket is handy to accurately submit at the price you want.
After clicking submit you will see your order indicated with a blue circle to show it is a buy order. If it was a sell it would be red. You can tap the blue circle to bring up the details of the order and it also gives you the ability to pull the order with the pull order button