Hi Duncan, I watched a few videos to understand your DCC system. Follow these steps: 1. connect decoder with servo and try to move with onboard pushbutton (press button once shortly) 2. push program button on board for more than 2-3 seconds while LED starts flash (use manual) 3. push SELECT ACCY button on your controller and enter address of decoder using numeric buttons 4. press button 1 or 2 to move servo and store the new address of decoder (check screen) 5. to select servo range press program button for more than 2-3 seconds, then press shortly until the LED lights up continuously 6. push SELECT ACCY button and enter value 50 (in your case 0050). Value 50 means 90 degrees and move servo with button 1 or 2. 7. to setup servo range use the same method like above (value 1: fast, value 20: very slow) I hope I could help you. Have a nice day! Szabi