When you predict the price of an asset to decline, you can sell the asset and buy it back when it falls.

For example, if you sell 10 STEEM/USDT @ $0.33, you will have more STEEM When buy back at @ $0.25. Then you can calculate how many Steem you have made and multiply it with the current price. If this is confusing, you can consider only buying positionin the spot market or you trade using the futures market.