mouse click does not work during game

Hi, im using an architectural template and am trying to learn blueprint to change matarials.
I followed video and made Blueprint Class, Level Variant Set and Widget Blueprint.

When I play the level the mouse click does not work. How can I make the mouse click make the blueprint change the materials.

Any help is appreciated, Thank you in advance!

  • what are you clicking on?
  • in which BP is the click implemented?