Hi!
To get the chair running, I recommend taking a closer look at the YAWController BluePrints, where you can see how the inputs are passed to the chair.
For those who want to develop in Unreal Engine for the YAW VR Chair, I have successfully upgraded the demo project from Unreal Engine 4.25 to Unreal Engine 5.4.3. Although the demo car with the vehicle in front is missing, I believe you will be able to work better with the controls and save hours of converting: YawVR_UE4 5.4 - 4.zip - Google Drive
Alternatively, I recommend checking out this link and the accompanying documentation, which will help you gain a better understanding of the signals.