Adding authentication to website directly from the general domain of the website

Hi, Im new here so sorry if I did somthing wrong,
I have a full stack web application, using vue 2 and node.js that allready deployed at heroku and in the future will become a progressive web app.
I want to implement Auth0 by that when the clients get to the general domain of the website they will redirect to auth0 and only then redirect to the application.
So first is it possible? and if it is I didnt found any example for same situation…
do i implement it on the server side or the client or both?

thank you for your help