Steps to do:
- Upload Demo folder in the package to your server. In most cases you will put it under the public_html folder, www root folder (windows hosting) or the root folder of your server.
- Create database by follow this tutorial https://www.drupal.org/docs/8/install/step-3-create-a-database and import sample database (database.sql.zip).
- Change the database info in sites/default/settings.php to match the database name, user and password for your new created database (see code below)
- Login with default admin account is: username: admin, password: admin
- Goto Configuration => Media => File system to check and correct the permission to make sure the public folder and temporary folder is writeable by web server.
$databases['default']['default'] = array ( 'database' => 'DATABASENAME', 'username' => 'DATABASEUSERNAME', 'password' => 'DATABASE_PASSWORD', );