How to get the SteamVR Inputs using OpenXR in Unity?

I enabled in Unity the OpenXR VR mode.

Then I enabled the HTC Vive interaction profile and others

After that I can see the world and I can get the Hand positions of the HTC Vive controller, but I can not get any input, How can I get for example the Trigger button press event?

I am using the following code:

private UnityEngine.XR.InputDevice inputDevice;

public bool isIndexTriggerPressed()
    {
        bool triggerValue = false;
        inputDevice.TryGetFeatureValue(UnityEngine.XR.CommonUsages.triggerButton, out triggerValue);
        if ((!previousIndexTriggerPressed) && (triggerValue))
        {
            previousIndexTriggerPressed = triggerValue;
            return true;
        }
        previousIndexTriggerPressed = triggerValue;
        return false;
    }

Is this the right code?, How can I get the trigger press event?

The only way that I get it to work was using directly the SteamVR Unity plugin.

I dragged the "[CameraRig]" object that is localized on the SteamVR/Prefabs directory, to my Scene.

I used the following code to get the inputs:

private GameObject controller;
private SteamVR_Input_Sources inputDevice = SteamVR_Input_Sources.LeftHand;

public void setInputDevice(SteamVR_Input_Sources inputDevice)
{
    this.inputDevice = inputDevice;
}

public void setController(GameObject controller)
{
    this.controller = controller;
}

public GameObject getController()
{
    return controller;
}

public Vector2 getTrackPad()
{
    return SteamVR_Actions.default_Trackpad.GetAxis(inputDevice);
}

public bool isHandTrigger()
{
    return SteamVR_Actions.default_GrabGrip.GetState(inputDevice);
}

public bool isHandTriggerPressed()
{
    return SteamVR_Actions.default_GrabGrip.GetStateDown(inputDevice);
}

public bool isHandTriggerReleased()
{
    return SteamVR_Actions.default_GrabGrip.GetStateUp(inputDevice);
}

public bool isIndexTrigger()
{
    return SteamVR_Actions.default_GrabPinch.GetState(inputDevice);
}

public bool isIndexTriggerPressed()
{
    return SteamVR_Actions.default_GrabPinch.GetStateDown(inputDevice);
}

public bool isIndexTriggerReleased()
{
    return SteamVR_Actions.default_GrabPinch.GetStateUp(inputDevice);
}

public bool isMenu()
{
    return SteamVR_Actions.default_Menu.GetState(inputDevice);
}

public bool isMenuPressed()
{
    return SteamVR_Actions.default_Menu.GetStateDown(inputDevice);
}

public bool isMenuReleased()
{
    return SteamVR_Actions.default_Menu.GetStateUp(inputDevice);
}

Dont forget the bindings Window -> SteamVR Input