Casting question

Hey gang,
I am trying to add BluePrint functionality to toggle the checkbox state on the HUD that will pause the game via Keyboard Input or clicking with mouse cursor. I have started with the ThirdPersonTemplate. My HUD on Event Begin Play creates my UI BP that contains the checkbox. In the ThirdPersonCharacter BP I have an InputAction Space that I am able to FlipFlop between the Game Paused/Unpaused however I want the Checkbox on the UI to reflect that so I added a Cast To UI node to drive the Set Checked State however I am lost as to what Object Reference the Cast To UI node is looking for.

Can someone please help me out? Thanks.