To get Google+ App Detail, go and visit the https://console.developers.google.com/project
page. You need to login in with your Google account if you aren't already. Then the Google API Console page will load and should look similar to the one shown in the image below:
Note: You must have to add Email Address and Product Name on Consent Screen page. Without this info your apps will not work and always generate a invalid client id error.
Note: When you enter the URL of your website in to the Website field, make sure that it does match the URL of your website 100%. This means, if you go to your website and then check the URL in the browser and the URL does look like
http://www.domain.com then you need to enter the exact same URL. If your website URL is http://domain.com then you need to enter it that way, without using the www at the front of the name.
Important: Use the "Authorized Redirect URI" field same as the Google+ callback url meentioned on the social login setting page. If these entries do not completely match the URL of your website, the application won't work and it will show an error message whe you try to connect to the App.
When you copy and paste all the needed IDs and Keys, make sure, that you don't have any empty spaces, either at the beginning nor at the end of these entries. If you have any empty spaces, then the Application won't work and will show an error message when you try to connect to the App.
After you entered the Google+ Client Id and Client Secret, click on the "Save Changes" button within the plugin's settings page.