This opens part of the notification panel along with several of the quick setting tiles at the top of the screen (i.e. the buttons with the icons for Wi-Fi, Bluetooth, etc.). Now the whole panel is open revealing even more of your quick setting tiles. This opens a pop-up list of devices you can connect to. On some Android phones, this option may say "Screen Mirroring" instead. If you don’t see one of these options, you may have to swipe right to the second page of notification tiles. Your Android’s screen will appear on the TV. Everything you do on your phone will appear on the TV as well. On some apps you can turn your phone sideways to show your phone's screen in landscape mode.

TL;DR in Vietnamese:
Vuốt xuống từ trên cùng của màn hình chính. Vuốt xuống một lần nữa. Nhấn SmartView hoặc Cast (Truyền). Chọn tivi của bạn.