On Robinhood, setting a stop-loss order is simple. First, open the Robinhood app or website and log in to your account. Select the stock you want to set a stop-loss for, then tap on "Buy" or "Sell" and choose "Sell" (even if you don’t own the stock yet). Next, you'll see the option to select a "Stop Loss" order. Enter the price at which you want to trigger the order and confirm the transaction. If the stock reaches the stop-loss price, Robinhood will automatically sell the stock at the best available price.