Open Website (https://console.developers.google.com)
Then select create projects and fill the form –
Then select APIs and auth in the left side menu –
Then select credentials which are listed under APIs and auth –
Create client ID –
Choose Web Application –
Then choose the corresponding email –
Then fill the form and click save button
Then give website URL and callback URL –
Then copy CLIENT ID, CLIENT SECRET and REDIRECT URIS and give it in back end. –