Downloading an app to your Android device from the Google 'Play Store' is really simple. This guide will walk you through the procedure step by step.
Steps

Step 1. Open the Google 'Play Store' application

Step 2. Log in by entering your Google account details

Step 3. Search applications
After logging in, you will be able to search through the many applications available in the 'Play Store', including games, music applications, etc.

Step 4. Install the chosen application
Select the application you want to download and press the 'Install' button.

Step 5. Accept application requests
The application will ask for access to some features of the device, simply select the 'Accept' button.

Step 6. Wait for the installation to complete
The time required varies based on the size of the application. As soon as the installation is successful, you will see a notification appear on the notification bar.
Step 7. Log in to the application
Done! Now you can access the applications panel and launch the newly installed app.