403 – Forbidden: Access is denied.

I am pretty much clueless when it comes to web design, so feel free to talk to me like I’m 5.

I am trying to help a friend get her website up. She purchased a WordPress theme. It is hosted on 1&1 (Windows.) I followed the steps on https://codex.www.ads-software.com/Installing_WordPress#Things_to_Know_Before_Installing_WordPress
but when I go to myforwarddesign.com/wordpress, I get this error:

403 – Forbidden: Access is denied.
You do not have permission to view this directory or page using the credentials that you supplied.

I don’t know what I did wrong or how to fix it.