To use Snapchat on a laptop, you must first have an Android emulator, such as the Bluestacks App Player, installed on the laptop. Bluestacks is free and lets you run applications designed for Android systems on the laptop. If you don't have it, download its setup file, and install it.
After successfully installing Bluestacks on the laptop, launch it, and wait for it to initialize. After it has loaded completely, click on the Search button located on the top left corner of the Bluestacks window. Type "snapchat" in the search field that appears, and click Search Play for Snapchat. A page showing Snapchat and other related apps appears. Click on the Snapchat app, and click on the Install option, which is on the right side of the app icon. Accept the terms and conditions, and wait a few minutes for the app to download. Install the app.
Instead of downloading and installing Snapchat from within Bluestacks, you can search its APK setup file from an Internet browser, download it to the laptop, and double-click it. Alternatively, right-click the APK file, go to Open With, and select Bluestacks. Snapchat installs in Bluestacks within a few seconds. After Snapchat's successful installation, open Bluestacks, go to All Apps, and click on the Snapchat icon to launch the Snapchat app.