There are two separate things people mean by this: drawing the levels on the chart to plan a trade, and placing actual orders through a connected broker. Both are below.
This is the planning tool, and it's the one to learn first.
The box immediately shows the risk-to-reward ratio, the distance in points and percent, and — once configured — the position size for your account.
To configure sizing, double-click the tool and set your account size and risk per trade. From then on, every box you draw tells you how many units to trade.
most people pick position size first and then find a stop that fits it. That is backwards. The chart decides the stop; the stop decides the size.
If your broker is integrated with TradingView:
Once live, you can drag the stop and target lines directly on the chart to modify the orders.
Without broker integration, the practical fallback is an alert at your stop level so you're told to act. It is not protection — it's a reminder — but it beats staring at a screen.