1. While signing up with pulse one cloud, you will be asked to enter your cloud instance hostname. If you enter pulsecloud as the instance name, then the url will be pulsecloud.pulseone.net. Use /admin at the end to get to the admin's web UI.
2. Normally, you will be using your business email (which you used during the sign-up process) and I believe after activating the instance by verifying your email address, you'll be asked to setup a password to login.