"Go short" means you sell first, then buy it back later. If you think AAPL is going lower, you can borrow shares from your broker and sell those. And when it goes down, you buy back shares at lower price and return them to broker with interest.

thanks!

To simplify - when you long, you bet on price going up. When you short, you bet on price going down. If you went short and price dropped 5%, your profit is 5% (minus commission, slippage, and some other stuff).

you borrow a share of stock from someone (like literally they loan it to you), then go sell it and keep the money.

eventually, you go to the market, buy another share of stock, and give it back. if you sold high and bought low, you make money.