Install Laravel Nova

 

1 - composer create-project --prefer-dist laravel/laravel admin "5.8.*"
2 - add/update in composer.json the following item

"repositories": [
    {
        "type": "composer",
        "url": "https://nova.laravel.com"
    }
],
Next, you may add laravel/nova to your list of required packages in your composer.json file:

"require": {
    "php": "^7.1.3",
    "fideloper/proxy": "^4.0",
    "laravel/framework": "5.8.*",
    "laravel/nova": "~2.0"
},

3 - php artisan nova:install

4 - php artisan migrate