Como Duplicar Pantalla En Android

I did not post any results because I could not get gnome-tweak-tool to work in Mate it seems to be installed but when I try adding the global dark theme in does not seem to work. I decided to just use the Appearance Preferences and add the dark theme. I cannot even get gnome-tweak-tool to appear so I can add it to my docky. it is installed but I can only launch it by using the terminal