A 404 after installing WordPress usually means something didn’t set up correctly. First, make sure WordPress is installed in the right folder (often public_html or the main domain directory). Also check that your domain is pointing to the correct hosting location.
If everything looks fine, try re-saving the permalink settings in WordPress once you can access the dashboard — that often fixes missing URL issues. And if you can’t access the dashboard at all, a quick reinstall usually solves it.