How connect doesn't connect variables?

Hello all, how connect button and button style node?

Could you elaborate a bit? It’s unclear what you’re trying to achieve.

Sure, i want to change texture button when i get event message. I find solution, please look attach screenshot, but i don’t understand how pin connected.
Solution: How do you change the appearance of a widget button once it's clicked? - UI - Unreal Engine Forums

Sure, i want to change texture button
when i get event message.

What’s stopping you from choosing a texture from the dropdown?
Which pin are you having problems with? In the screenshot you provided, everything is already connected.

I don’t understand how connect??

I see now. Get Style first and it should work.