Press the green button marked with "Install" or with the price of the application. If the button shows a price, provide your payment details in order to proceed.
In order to download an application, you first need to find it by using the search bar at the top of the Google Play Store's screen. If the application is free, the app displays a button just below the application's title that says "Install." If it costs money, the green button shows the price of the application. Press this button, review the list of permissions shown, provide payment details if necessary, and go to your device's main screen to find your new app.