If you want to use Vive Trackers for capturing hands, open BP_CapturePawn blueprint (VMK/Blueprints), then in properties of the CaptureDevice component change “Motion Controllers Role” from “Hands Only” to “Any Role”. And don’t turn on controllers unless you want to use them to capture, for example, feet.
If you want to use third-party tracking system (for example, Optitrack) for everything instead of SteamVR, you’d need to add SceneComponents (for example, OptiTrack Rigid Body Components) for all tracked points and then in the BeginPlay event call CaptureDevice::InitializeInputFromComponents.
Thanks for the info! Is there a way to ignore certain SteamVR devices, like an extra tracker that I would have on my body, and not use that for the IK rig?