To obtain a Google Client ID to use the Smart Optin app, you will first need to create a Google API Console project.
To do so, follow this guide provided by Google as we walk through it below: https://developers.google.com/identity/sign-in/web/sign-in
Create your Google Cloud Platform by heading to: https://console.developers.google.com/apis/credentials
You'll be prompted to enter your country and agree to their terms and conditions.
Then on the right side of the page click CREATE PROJECT.
Give your project a name and leave the Location as No organization.
At the search bar at the top, type "Google People API" and click on the phrase.
Hit the back button at the top to return to the homepage.
Then at the top of the screen click CREATE CREDENTIALS and select OAuth client ID.
Select Web Application and give it a name.
Under Authorized redirect URIs paste the complete URL of any/all pages where the Smart Optin App will be used.
Then scroll down and click CREATE.
You'll then be given a Client ID and Secret. Copy the Client ID.
Head to your Funnelish account and paste the ID in the provided box inside of the Smart Optin app in the global app section.
Click save changes, and make sure the app is enabled in the funnels you want!
And that's it!