Bluprint UI Widget

Hello everyone, I need to make it possible to change materials using a UI button.
I made a plan there, created a variable and attached a static grid there.
But in the widget I cannot specify a static grid, there is only a reference object, and it does not fit

1 screenshot of my blueprint

2 screen tutorial

Tell me how to implement a blueprint for changing materials using a button on the interface…

From the array element pull a pin and type
GET [insert mesh component name you have inside Tommba Statick]


Am I doing this wrong?

Yes, I meant the single element from array, so this: