If you're using Composer, you can simply add a dependency on deflate/php-sdk-deprecated to your project's composer.json file. Here's an example of a dependency on version 1.0.0:

{
    "require": {
        "deflate/php-sdk-deprecated": "^1.0"
    }
}

Alternatively you can also execute the following command in your project's root directory:

composer require deflate/php-sdk-deprecated

Using Git

If you already have git setup and want to use Deflate in subdirectory of your current project you can execute the following command:

git clone git@github.com:deflate/php-sdk-deprecated.git deflate/