How do I set up the Google sign up / log in so that after user authenticates, it sends them to another URL, not the Log-in / Sign-up URL?

In my website, whenever the user authenticates, they are redirected back to the log in page, which then sends them to the new website through a workflow I created. However, I’d like them to go directly to the website without the intermediary step where they are sent for a couple of seconds back to the log in page

In your google dashboard set the redirect URI to where you want the user to be redirected to

If I do that, I get this message from Google when user tries logging in:
Error 400: redirect_uri_mismatch

It’s as if it doesn’t recognize the originating URL