set_button function can enable or disable a button in a screen.
set_button [buttonId] [true, greyed, hidden or false]
Refer to the screens feature guide for more info
set_button parkButton true
true: Makes the button enabled and clickable (as long as clicking it is allowed, see screen buttons interaction tags)
false: Makes the button completely disabled and hidden
greyed: Makes the button disabled and greyed. It will be visible with semi-opacity, but not clickable
hidden: Same as