Android: A well-organised home screen is a thing of beauty. When you download a new app from Google Play, it adds an icon to your screen, destroying your work of art. Changing setting in the Google Play app solves that problem.
Head to the Google Play application, then go to its Settings from the three-line hamburger icon. Uncheck the "Add icon to Home Screen" option. You'll still be to add app icons manually, but they won't automatically add themselves when you download the app.