How to Use Your Laptop as a Second Screen for Presentations

When Do You Need a Second Screen?

Whether you are presenting to clients in a meeting room, running a training session, or sharing your screen on a TV in a clinic waiting area, connecting your laptop to an external display is a skill worth knowing. It is straightforward once you know the steps.

Connecting Your Laptop to a Display

Step 1: Identify Your Connection

Look at the ports on your laptop and the display (TV, projector, or monitor):

Common port types:

• HDMI — the most common connection. A trapezoid-shaped port found on most laptops and TVs
• USB-C / Thunderbolt — a small oval port found on newer laptops (MacBook, Dell XPS, Lenovo ThinkPad)
• DisplayPort — similar to HDMI but with one angled corner, often found on monitors
• VGA — a larger blue port with screw holes, found on older projectors and monitors

Step 2: Get the Right Cable or Adapter

| Your Laptop Port | Display Port | What You Need | |---|---|---| | HDMI | HDMI | HDMI cable | | USB-C | HDMI | USB-C to HDMI adapter or cable | | USB-C | USB-C | USB-C cable | | HDMI | VGA | HDMI to VGA adapter | | USB-C | DisplayPort | USB-C to DisplayPort cable |

Tip: If you present regularly, keep a USB-C to HDMI adapter in your laptop bag. It covers the most common scenario.

Step 3: Connect the Cable

• Plug one end into your laptop
• Plug the other end into the TV, projector, or monitor
• If using a projector, turn it on and select the correct input source
• If using a TV, switch to the correct HDMI input using the TV remote

Choosing a Display Mode (Windows)

Once connected, press Windows + P to open the display options:

• PC screen only — your external display is off, everything stays on your laptop
• Duplicate — shows the same thing on both screens (best for presentations)
• Extend — uses the external display as extra desktop space (best for working with two screens)
• Second screen only — turns off your laptop screen and only uses the external display

For presentations: Choose Duplicate so your audience sees exactly what you see on your laptop.

For working at a desk: Choose Extend to spread your work across two screens.

Choosing a Display Mode (Mac)

Automatic Detection

When you connect an external display, your Mac should detect it automatically. If not:

• Click the Apple menu > System Settings
• Click Displays
• The external display should appear

Mirroring vs Extending

To mirror (duplicate) your display:

• Go to System Settings > Displays
• Click Arrange
• Tick Mirror Displays

To extend your display:

• Go to System Settings > Displays
• Untick Mirror Displays
• Drag the display arrangement to match the physical position of your screens

Keyboard shortcut: On some MacBooks, press Cmd + F1 to toggle mirroring.

Presenting with PowerPoint

Presenter View (Windows)

When you connect a second screen and start a slideshow in PowerPoint:

• Open your presentation
• Click the Slide Show tab
• Check Use Presenter View
• Click From Beginning

Your audience sees the slides full-screen on the external display, while your laptop screen shows:

• The current slide
• Your speaker notes
• A preview of the next slide
• A timer

Presenter View (Mac)

• Open your presentation in PowerPoint
• Click Slide Show > Presenter View
• Start the slideshow

The same dual-view setup applies.

Presenting with Google Slides

• Open your presentation in Google Slides
• Click the dropdown arrow next to the Slideshow button
• Select Presenter view
• A new window opens with your slides full-screen — drag this to the external display
• The presenter notes window stays on your laptop

Wireless Display Options

If there is no cable available, you may be able to connect wirelessly.

Windows: Miracast

• Press Windows + K to open the Cast menu
• Select the display from the list (the TV or display must support Miracast)
• Choose Duplicate or Extend

Mac: AirPlay

• Click the Control Centre icon in the top-right menu bar
• Click Screen Mirroring
• Select the Apple TV or AirPlay-compatible display

Using Chromecast

• Open Google Chrome on your laptop
• Click the three dots menu > Cast
• Select the Chromecast device
• Choose to cast a tab, a file, or your entire desktop

Adjusting Display Settings

Resolution and Scaling

If text or images look blurry on the external display:

Windows:

• Right-click the desktop
• Click Display settings
• Select the external display
• Adjust Scale (try 100% or 125%)
• Adjust Display resolution to match the display's native resolution

Mac:

• Go to System Settings > Displays
• Select the external display
• Choose Default for display or adjust the resolution manually

Audio

When you connect via HDMI, your laptop may send audio to the TV or monitor:

Windows:

• Right-click the speaker icon in the taskbar
• Select the audio output you want (laptop speakers or external display)

Mac:

• Go to System Settings > Sound
• Under Output, select your preferred speakers

Troubleshooting

No picture on external display

• Check the cable is firmly connected at both ends
• Make sure the TV or projector is on the correct input
• Press Windows + P and select Duplicate or Extend
• Try a different cable or adapter

Picture is blurry or the wrong size

• Adjust the resolution in Display settings to match the external display
• Try different scaling options (100%, 125%, 150%)

No sound from the TV

• Check that the TV is selected as the audio output
• HDMI carries audio — VGA does not (you need a separate audio cable for VGA)

Wireless connection drops out

• Move closer to the display device
• Check that both devices are on the same Wi-Fi network
• Wired connections tend to be more reliable for important presentations

Laptop screen goes to sleep during presentation

• Adjust power settings to prevent sleep while plugged in
• In PowerPoint, Presenter View prevents sleep automatically

Need Help?

For help setting up meeting room displays or presentation equipment, contact helpdesk@netlumait.com.au or call 1300 521 162.