How to use iOS client from Google or should I use WebClient and why?

Rookie issue. I want to implement Google SignUp inside the iOS application using Auth0, but I am too confused. I did it, but I am not sure how correct is it.

Google docs says that I MUST stick with “iOS client” option. But this option, won’t give us clientSecret that I need to set, when create “Social” connection inside Auth0.

Instead, I created a WebClient in Google project and used provided clientId and clientSecret to connect with Auth0. Downloaded an Auth0 SDK for Swift and followed instructions. Tested on iOS simulator and signup works perfect.

Question: Should I continue with WebClient from Google or I got something wrong, where to find docs why does it work that way, or maybe I can use iOS client also somewhere?

Question: I don’t understand if should I create an API in Auth0, cause I am only created an Application ?

Question: When I will have Apple TeamID and working bundleId, what changes should I do?