1. Log into your WordPress site by going to your url with /wp-login.php added. Ex: www.mysite.com/wp-login.php
2. Click on the yellow box at the top of the dashboard, OR go to Dashboard- Home- Updates.
3. Make sure that your site is backed up.
4. Click on the blue Update Now button.
5. Your new version of WordPress will install.
6. Make sure that everything on your site works properly.