OK, the harder I try to make things clear, the muddier they get!
2 pages can be less than 2 minutes of time in some cases. I wanted to say how you can see the whole album laid out. But, it's not necessarily the whole album.
I work by "event" in general, which could be an event (vacation, day at the zoo, weekend at grandmas....) or series of events (Christmas from several years).
Basically, you take the stack of photos that go together in the same album and see how and where they fit and where page breaks and 2 page layouts can be. So, I may have 1 page events, but usually, it's a series of 2 page LOs.
Clear as mud? Really, it's easier to do than talk about!