php - Google plus login functionality and composer library install -

I am working on the Google + login functionality for the purpose for which I https: // developers Google.com / + / quickstart / php url. I have done all the suggested instructions

1. Enabled Google Plus API
2. Install the PHP Quick-Start App

In the second step To run the signin.php file, they are suggesting to install the composer and run the command php composer.phar install . I have already installed Musician on my machine and it is up to date.

I can not find the way to run php composer.phar install , as the code is cloned from http: //github.com/googleplus There is no composer.phar file in /gplus-quickstart-php.git (only composer.json and composer.lock files )

signin.php File

How do I install these dependencies as fatal error autoloader.php not found ?

I think using Musician I need to download the directory from https://github.com/google/google-api-php-client.git It's written in the composer.json file.

Tell me what should I do?