How to access Google oAuth with cURL?

Question

Dears, I tried many ways to get token from Google, following the many tutorials for both configuration at Google-console and cURL command with no success!

I started following Google-developer with no success. I tried to follow the many tutorial where I found some of the code old and dated while other pointing to wrong URL and further ones giving wrong indication about the Credentials to be created at Google-console side.

I need it to go on with a local app and I have cURL library available.

I hope someone knows the right procedure to succeed and is so kind to share it here. I am sure the right answer will get many thanks from a lot of user!

My personal thanks for trying.