I've updated the README.MD with some stuff, and tried to clear what the 'Hosted Param' field is for. A step by step guide for setting up everything on the Google side will be done shortly.
Sorry for the delay's in getting back, I've been up the wall with work trying to get things up and running and stuff to manage continuously.
This is what my Credentials page looks like in the Google API Console:
https://i.imgur.com/bNslnFb.png
For Javascript Origins: I have set both http and https on live server and the http for my local,
For Authorised redirect URL, it ends in /auth/google.
I will clear this up in the documentation