Make sure your project you just created is selected in the Projects menu just right of ‘Google APIs.’ Then click on the main menu.
Select Identity > Service Accounts:
Create a service account:
Enter an account name and optional description. The account ID will be automatically generated.
Click Create on the service account details.
Click Cancel on the next screen, service account permissions, as you don’t need to define any roles. You’ll return to the service account dashboard and will create a key.
Click on Actions for the service account you just created, and select Create Key:
In the resulting pop-up, ensure that the JSON option is selected, and click Create to download the json:
Store it in a secure place, as you will need it later in the setup.
Next Step: Enable the APIs