Most laptops have least one port that can be used to connect a monitor, be it HDMI, VGA, DVI, or DisplayPort. However, some of the latest ultraportables may require an adapter which isn't always supplied in the box.
If you have a PC, it should be just as easy to connect a second screen: just check which ports are on the rear that match one on your second screen.
If you don't already have a screen, then choose one with an input that matches your laptop's output. Sometimes it's possible to mix and match some of the digital options. For example you can convert DVI to HDMI with a basic cable. But you cannot convert VGA (which is analogue) to HDMI (which is digital).
The newest laptops may have only a USB-C port (also called Thunderbolt 3). This the the same physical connector you'll find on most new Android phones. It's reversible and you can buy a USB-C to HDMI cable, or USB-C to DisplayPort, depending upon which one of these inputs your screen has.
Here's what to look for on both your laptop and screen:
How to configure a second screen in Windows
With the screen physically connected, it's time to configure Windows to use both screens. We're using Windows 10 here.
Step 1. Usually, when the screen is turned on, Windows will automatically detect it and enable it. If you don't see anything on the screen, use its buttons to select the correct input. Most will auto switch to the input receiving a video signal, but not all do.
Step 2. Click Start, Settings and System. Here you'll find the Display menu (by default) to reach settings like orientation, size and brightness.
Step 3. You have various options for what to display on each of the two screens.
• Duplicate: The second monitor mirrors what's on your laptop's screen.
• Extend: The Windows desktop is spread across the two monitors.
• Show only on 1 or 2: Only one of the displays will be used (click Identify to see which is which).
Another way to switch between these modes is to look for a function key on the top row of keys on your laptop which shows two monitors. Press the Fn key and that function key and it should toggle through the various configurations: laptop display only, laptop + external screen, external screen only.
Step 4. If you choose 'Extend these displays' you can drag monitor 2 in the diagram to where it is physically. If the resolution is larger, the rectangle will be larger in the diagram. You can place it so the bottom edges line up, or you can have an equal area top and bottom: it's completely up to you.
Step 5. Adjust the resolution for each screen to improve the quality of text and video shown onscreen. From the Display menu, select Advanced display settings. Use the drop down box to adjust the screen’s resolution. It’s advisable to use Windows’ recommended resolution for each display.
For screens with high resolutions, you'll probably want to use the 'Change the size of text, apps and other items' slider to make sure everything is easily readable. Typical settings are 150%-250%.