To register you have to go to
https://licensing.symantec.com/acctmgmt/index.jsp
log in using your username and password.
You would only click on the version upgrade link if you were a previous BE 10 user with a valid maintenance contract. This just allows you to download the new 11d software (which is the route that I went). You shouldn't need to do this if you already have a copy of 11d. If you don't have 11d then they should have sent you your notification ID and customer number in an e-mail (that's how they did it for me).
Now here is the tricky part that never quite worked for me the way it was supposed to.
1) Click on "License Management (Manage Licenses)"
2) Enter your old Serial numbers (this includes the components not just BE, e.g. I used my BE 10, Oracle Agent, and library expansion serial numbers) and customer number and pray that the system recognizes it. It would never recognize mine and I had to use my customer number alone without serial number.
3) Once all of your old BE 10 license numbers are entered you should be able to go back to the "License Management (Manage Licenses)" link and search for your license using the "Your License Catalog" section of the page.
4) After searching for your license (still BE 10 at this point) you click the "View Details" link beside each license number. Within that link there is another link that says "Upgrade License". If you click this link you will receive an e-mail with the new 11d license for BE and all the components that you entered into the site. You must click the "Upgrade License" link for each serial number (Oracle Agent, Library Expansion, and so on).
Of course when I clicked the "Upgrade License" link I got an error and it took a month of calls to Symantec to get it sorted out. But eventually they fixed whatever was wrong on their end and clicking the link worked. I hope this helps.