The process of setting Stop Loss/ Take Profit on your orders when you open positions will be as follows:

Visit the "Trade" page, choose the product, select "Buy" or "Sell," and set the Stop Loss / Take Profit.

The process of setting Stop Loss/ Take Profit on your opened orders will be as follows:

Visit the "Order" page, click "Open Positions," select the order you want to Apply this setting to, set the price.