You may want to change the amount of time before your laptop display turns off or dims while on battery or while connected to a power adapter. To do this go to the Apple Menu --> System Preferences --> Battery Select Battery or Power Adapter on the side. Also see this article from Apple's support site …
This guide will show you how to enable display mirroring on your computer. Step 1: Plug in your display Step 2: Open “System Preferences” from the Apple menu in the menu bar. Step 3: Open Displays Preferences. Step 4: Click on the “Arrangement” Tab. Step 5: Check the box labeled “Mirror Displays” Step…