In order to configure Google, you must first create a Google project in order to obtain a Client ID and secret. You may do so at https://console.developers.google.com/
Create a Project
If you want to create a new project, click the arrow next to the existing project.
Then, click on "New Project" at the top right of the popup.
Give your project a name and click "Create".
On the next page, visit the "Credentials" tab. Click the "OAuth consent screen" sub-tab. On this screen, Google only requires you to enter the Product name field. You are welcome to fill out any others. Save your changes.
Now visit the "Credentials" sub-tab. Click "Create Credentials" and then "OAuth Client ID" in the popup.
Next, select "Web application" for application type. Give your application a name. For "Authorized redirect URIs", you will simply use your TML login page URL with the provider appended as a query argument. By default, this would be http://yoursite.com/login/?provider=google. Click "Create".
Obtain Client ID & Client Secret
Copy and paste your Client ID and Client Secret into their corresponding fields in the TML Social settings.
Don't forget to check "Enable" and then click "Save Changes".
Login With Google
You will now see "Log in with Google" on your login form.