Method 1.

 1. Open Steam. This application resembles a white piece of machinery on a blue background.

2. Log into Steam if prompted. Type in your account name and password, then click LOG IN. This will log you into Steam.

3. Click the STORE tab. It's at the top of the Steam window.

4. Select a game you want to purchase. Daily deals, recommended games, new releases, and employee picks appear on the main STORE page. If you want to ...

5. Scroll down and click Add to Cart. This green button is below the "Buy [Game Name]" heading in the middle of the page.

6. Click Purchase for myself. It's a green button near the top of the pages.

7. Select your payment information. you can pay through PayPal, or you can use a credit or  debit card.

8.Click purchase. This option is in the middle of the screen. Doing so will complete your transaction and add the game to the stream library. 

9. Click the library tab. It's in the upper -left side of the steam window.

10. Download your game. Double click  your game's name in  the left-hand toolbar, then click ok with prompted. This will begin downloading the game to your computer.

11. Once your game finishes downloading to your computer , double -clicking its name in steam will begin running it. You have successfully installed a game on your PC.