On your Mac, click in the menu bar at the top of your screen.
Choose your Apple TV. If you don’t see your Apple TV, make sure that your Mac is connected to the same Wi-Fi network as your Apple TV.
If an AirPlay passcode appears on your TV screen, enter the passcode on your Mac.
To change the size of your desktop mirrored on your TV, click in the menu bar. Then select Mirror Built-in Display to match the size of your desktop or Mirror Apple TV to match the size of your TV.
AirPlay also lets you use your TV as a separate display for your Mac. Just click in the menu bar, then select Use As Separate Display.
To stop mirroring or using your TV as a separate display, click in the menu bar, then choose Turn AirPlay Off. Or press the Menu button on your Apple TV remote.
Directly to Computer
Connect the video cable (usually VGA or HDMI) from the projector to the Mac. In order to do this, you will most likely need a Mac adapter cable.
Adapters vary depending on your computer’s video inputs.
Once the Mac and projector are connected, click on the Apple Menu in the top left corner of your screen.
Select System Preferences from the drop-down menu.
Select the Displays icon.
When the Displays window appears, click the Detect Displays button.
At this point your Mac and projector should be synchronized. If not, try following these steps:
Click on the Apple Menu in the top left corner of your screen (Step 4)
Select System Preferences from the drop-down menu (Step 5)
Select the Displays icon (Step 6)
When the Displays window appears, select the Arrangement tab within the menu bar
Check the Mirror Displays box in the lower left-hand corner of the window
After checking this box, wait several seconds. Once the displays are mirrored, you should see the same image on both your projector and computer.
Use Screen Mirroring to see the entire screen of your iOS device on your Apple TV.
On your iOS device, open Control Center and tap Screen Mirroring.
Select your Apple TV from the list. If you don’t see your Apple TV, make sure that your iOS device is connected to the same Wi-Fi network as your Apple TV.
If an AirPlay passcode appears on your TV screen, enter the passcode on your iOS device.
Your TV uses your iOS device's screen orientation and aspect ratio. To fill your TV screen with the mirrored iOS device screen, change your TV's aspect ratio or zoom settings.
To stop mirroring your iOS device, open Control Center, tap Screen Mirroring, then tap Stop Mirroring. Or press the Menu button on your Apple TV remote.
Tap . In some apps, like Photos, tap , then tap AirPlay.
Choose your Apple TV. If you don’t see your Apple TV, make sure that your iOS device is connected to the same Wi-Fi network as your Apple TV. Need help?
To stop streaming, tap in the app that you're streaming from, then tap your iPhone, iPad, or iPod touch from the list.
in the menu bar at the top of your screen.
in the menu bar. Then select Mirror Built-in Display to match the size of your desktop or Mirror Apple TV to match the size of your TV.
.
Screen Mirroring.
. In some apps, like Photos, tap 
, then tap AirPlay.
in the app that you're streaming from, then tap your iPhone, iPad, or iPod touch from the list.