Settings issues

Hi,
I’ve just read your post : https://support.google.com/mail/?p=BadCredentials k6sm5192735wrx.41 – gsmtp

The fact is that I’ve already registered “my project” and I do not know how to make the settings for the oauth authentification : I can’t find the credential types. I’ve got already the key id user and secret key. What’s next for me ?

And I if I try to use the login way instead, it doesn’t work. I thought I had to register my mail gmail adress and the password going with it.

Can you please explain me precisely authentification and loging ways in my case so that I can succeed in sending mails ?
Thank you very much.