When you first pull up the website, go to the bottom of the page. There is a link that says, "I'd like to get started." Click on that and it will walk you through the registration and give you all the info you need. After you've gone through all of that, you can go into the Panic Program itself. It will take you through one week at a time. To get into it, you just log in at the top of the page, which will take you to your home page where you can either "continue with program" which will take you to the session you are on, or you can get into your Session Diary from this page.
I hope that helps or at least makes sense. It's been a long time since I actually started the program, but if I remember right, that's how you do it. Let me know if it's not. I'll try to help you figure it out. ;p