Implementing auth0 in my app

I’m a newbie and working on a healthcare app where users can register or login as either a healthcare provider or recipient.
The project has been divided into two, backend(nodejs) and frontend(reactjs).

I’m trying to make sure that users only interact with frontend and frontend interact with backend. I want to implement authentication using auth0 in the backend as I’ve read its the safer option.

I want to know if it’s possible and if yes, how do i achieve this.

Also, i need to ask the user for some more information than the req.oidc.user has after registration, it means that i have to redirect the user after passing auth0 verification during signup to a page different than i specified in the callback url, how can i achieve this? Kindly help

PS: I just saw what i wanted manifest, when i was signing up now. After auth0 verified me, it took me to a page to ask further information this is what i want to do too from the backend even though i have a frontend.