Granada City Pass

Your post is not clear. When you say "their website," are you referring to the Alhambra?

If you are, then the Granada City Pass is convenient if you are going to enough other covered attractions. For me, including bus rides, I only made it pay off because I went to the Science Museum, in addition to the places listed in Rick's book. When you buy the pass, you request your Alhambra reservation time (you list your first few choices of times, and when you get your pass, they tell you which time you got). Ask for a time on the day after you arrive, in case you get one later than you wanted (if it's on your arrival day and later than you arrive, you miss it).

If you are not going to enough covered sites to make the Grenada City Pass pay off, you can just get Alhambra tickets. Rick's book has the details of the latest procedures. The official website is here: http://www.alhambradegranada.org/en/info/ticketsale.asp. You want a "daytime visit" so you can see everything. If you want to book a tour, you can, but the audioguide is quite thorough.

As Rick explains quite well, the time on your ticket is for the Nasrid Palace and is very strict. But once you enter the Palace, you can spend as long as you like. The Nasrid Palace time also determines if you have a "morning" or an "afternoon" ticket. You can visit the Generalife Gardens and Alcazaba, once each, during your allotted half-day (no set time slot other than before 2 PM or after 2 PM). There are also parts of the Alhambra complex that do not require tickets and can be visited at any time.