The “Future Rolls” page shows all available future-perpetual and future-future roll instruments. If a roll instrument is selected, the corresponding 'order entry', 'order book' and 'recent trades' interfaces will be shown. In contrast to individual futures contracts, only market and limit orders can be submitted for roll instruments.
If you buy one BTC-28JAN22-PERPETUAL, you buy the first contract (i.e. BTC-28JAN22) and sell the second (BTC-PERPETUAL). The reverse is true if you sell one BTC-28JAN22-PERPETUAL. Roll orders are always executed in the two outright futures legs. Roll prices are often positive if the futures are trading at a premium to the perpetual and negative if the futures are trading at a discount.
Please see our Contract Specifications for more information.