How can I log in to Facebook through Google ?

You cant get into your Facebook through your Google Account thats not Possible

Google what?  Google is a multi-million dollar, international company.  Do you own it?

What application from Google is it you wish to login to facebook with?  Are you talking about Google Chrome, their web browser?  If so, simply type facebook.com in the address bar at the top of the screen and press Enter.

You will, of course, need to have an account that you have the password to enable you to login.  If you don't have an account you can simply make an account, the details will be on the page that you get when you type facebook.com in the address bar and press Enter.