During the installation process, it works you through the configuration steps and build process. It even tells you to make sure that you have port 8140 open in the firewall.
The default account = admin.
The password for that account, is whatever was typed into the fields( 1st initial, 2nd confirm).
If you have a working DNS, and you have opened up port 8140/tcp, then browse to the hostname you provided during the installation phase (also through a web interface) on port 8140.
For example, if the hostname you gave it was puppydog; browse to
https://puppydog, because the site is already SSL secured; granted the certificate was issued by a Puppet CA, as opposed to your own corporations CA.