As @stevietee10 said i you can let us know what flight controller you are using we can help you. But usually spectrum requires a UART port (and a 3V output depending on your receiver), but most FC support this
I emailed Rotorgeeks to ask them about this issue. They said I could use one of these receivers or satellites. I need some clarification though. Do I need both the receiver and satellite? In the heli world, I don’t need both. If I buy just the receiver, can I plug in the existing leads, bind it and we’re good to go?
As Alex stated, which receivers you can use depends firstly on your transmitter, and secondly on your flight controller.
Spektrum use two systems, DSM2 and DSMX, and while some receivers can decode both systems, many can’t, and the Lemon you linked to is showing as DSMX only, while other Spektrum and Orange receivers are capable of both systems.
Your flight controller requires either a PPM signal, or a serial bus protocol, (in your case a Spektrum satellite to match you Tx protocol), and obviously your receiver must be capable of either PPM or a direct satellite conection, (wiring details shown at the bottom of the flight controller page you linked).