Long: Stock is 25. You want to buy 100 at 24 --> Qty 100, Buy@limit 24. Will be executed when stock drops to 24 (simplistically).
Short: Stock is 25. You want to short 100 at 26 --> Qty 100, Sell@limit 26. You will be short 100 shrs if stock rises to 26, if you don't already have a long position in the stock, and it is shortable.