Final answer:
To restart an app after installation on a device or emulator, you can use its icon, which is usually found on the home screen or app drawer.
Step-by-step explanation:
Once you install an app on a device or emulator, you can use its icon to restart it. After installation, an app's icon generally appears on the home screen or app drawer of your device, allowing quick access to launch the app.
When dealing with an emulator, which is a virtual environment imitating another operating system, the process is similar. You locate the app's icon within the emulated environment and click or tap it to start the application. It's worth noting that emulators are commonly used for development purposes to test apps on different platforms without needing the actual hardware.