You log into www.carnival.com. There will be a tab that asks you to fill out all of your pre-cruise information. You will put in your booking number to get that. It will guide you through the process.
Life is too short to let the ship of your dreams sail without you.
Carnival Destiny Feb. 2006
Carnival Fascination Feb. 2007
Royal Caribbean Grandeur of the Seas Feb. 2008 The DTW & MsBJ tour
Carnival Valor MsBJ and Dina Feb. 2009
Carnival Glory MsBJ and Dina Feb. 2010
Carnival Dream MsBJ and Dina Feb. 2011
Once you are registered with Carnival and add your booking number you can start filling out your Fun Pass, Sail & Sign Account Preferences, and Documents Preferences(Electronic Documents are highly recommended btw, because there can be last minute changes that may not show up on paper tickets but will on electronic ones). You can save your info and return later if you do not have everything together yet. Just remember you have to finish it before a certain time before you cruise. I am not sure how soon before, but I do not think it is any more than a week at most.
Actually, you do not have to register with the Carnival website to be able to fill out your pre cruise info (Fun Pass). You will need your Booking Number, last name, ship name, and sail date to fill out the fun pass. As a group leader I fill out lots of fun pass info for fellow group cruisers. Rick