The proper way to connect your Spektrum wireless interface is:
 
Plug in the USB interface to the computer
Press and hold the bind button on the Spektrum wireless interface.
Attach the Spektrum wireless interface to the FS One USB Interface.
The light on the Spektrum wireless interface will begin to flash, release the bind button on the Spektrum wireless interface.
Press and hold the bind button on the back of the transmitter and turn the transmitter power on, once the transmitter is in bind mode (light flashing on the back of the transmitter) release the bind button.
The lights on both the transmitter and the Spektrum wireless interface stop blinking when the binding process is complete.
Start FS One.
 
The transmitter is now bound to the Spektrum adapter. To set up the transmitter within FS One:
 
Start FS One
Go to single player Freestyle
Select Transmitter
Within Edit Transmitter go to the drop down menu (the menu with the little arrow pointing down) in the upper right hand corner of the screen and select JR 8- Ch Emu + FS One.
Use the scroller bar to select the MiG 15 and press OK
 
Note: If you are using your own transmitter on a regular basis, it is suggested that you to go to options and uncheck the option "Auto-Load Radio/Controller". Normally, in FS One, the default controller is automatically selected every time you select a different aircraft. If you uncheck this option, you will have to select the transmitter manually, so you can just leave it on the Spektrum transmitter instead of re-selecting a transmitter every time you change aircraft.