Installation & setup in Laravel

Medialibrary can be installed via composer:

$ composer require spatie/laravel-medialibrary:^4.0.0

Next, you need to register the service provider:

// config/app.php
'providers' => [
    ...
    Spatie\MediaLibrary\MediaLibraryServiceProvider::class,
];

And publish and run the migration:

$ php artisan vendor:publish --provider="Spatie\MediaLibrary\MediaLibraryServiceProvider" --tag="migrations"
$ php artisan migrate

Publishing the config file is optional:

php artisan vendor:publish --provider="Spatie\MediaLibrary\MediaLibraryServiceProvider" --tag="config"

The config file contains a number of default values:

return [

    /*
     * The filesystems on which to store added files and derived images by default. Choose
     * one or more of the filesystems you configured in app/config/filesystems.php
     */
    'defaultFilesystem' => 'media',

    /*
     * The maximum file size of an item in bytes. Adding a file
     * that is larger will result in an exception.
     */
    'max_file_size' => 1024 * 1024 * 10,

    /*
     * This queue will be used to generate derived images.
     * Leave empty to use the default queue.
     */
    'queue_name' => '',

    /*
     * The class name of the media model to be used.
     */
    'media_model' => Spatie\MediaLibrary\Media::class,

    /*
     * When urls to files are generated this class will be called. Leave empty
     * if your files are stored locally above the site root or on s3.
     */
    'custom_url_generator_class' => null,

    /*
     * The class that contains the strategy for determining a media file's path.
     */
    'custom_path_generator_class' => null,

    's3' => [
        /*
         * The domain that should be prepended when generating urls.
         */
        'domain' => 'https://xxxxxxx.s3.amazonaws.com',
    ],
];

Finally you should add a disk to app/config/filesystems.php. All files added to the media library will be stored on that disk, this would be a typical configuration:

return [
    ...
    'disks' => [
        'media' => [
            'driver' => 'local',
            'root'   => public_path('media'),
        ],
    ... 
];   

Don't forget to ignore the directory of your media disk. Using git? add a .gitignore file to the directory where the media will be stored.

If you are planning on working with image manipulations it's recommended to configure a queue on your service and specify it in the config file.

Want to use S3? Then follow Laravel's instructions on how to add the S3 Flysystem driver.