re the documentation - it says get yourself an OAuth 2.0 Credentials app created at https://console.developers.google.com/apis/credentials.

but when I get to that page I have no idea what I am supposed to do?

do I have to go to 

Configure Consent Screen?

if so what do I put when I get there?!

internal? / external?

app name? support email?

so many questions - a bit of clarity would be greatly appreciated