Ok so
I want the app like
When the screen is in portrait then the button 1 should be visible, button 2 should not
And
when the scene is in landscape then the button 2 should be visible, button 1 should not
There should be special blocks under Screen1 you can pull in for screen orientation possible values. Double check in the Blocks Editor.
If that doesn't work for you, check if the Screen1 Height is more or less that the Screen1 Width.
You might need to do this in a one shot Clock Timer event after the orientation has changed or after startup, since it takes a moment for the values to change.