How can I create a variable from a blueprint

Hello,

I am trying to use buttons in my HUD widget to control texture changes in my blueprint. I’m sure I am on the right track but I can’t figure out what’s wrong with my variable creation. I keep getting the message log error “Access None…”

That’s my setup.

Here is where I call the HUD in game

Not sure what’s the causing the issue, but I think it’s my variable creation. Any help is appreciated. Thank you.