As long as you do not determine everything in advance, or at least give yourself leave to change the predetermined stuff in response to character actions then you have determined stuff in advance with out pre-determining the story.Here the perception of an issue:
(1) How does the adventure play out? Determine the encounters or events that take the characters from the beginning of the adventure to the end.(2) the events of the story shouldn't be pre-determined
(1) and (2) - which are both direct quotes - seem like conflicting instructions to me. How can I determine in advance without pre-determining?
I will re-iterate my initial comments. This discussion is premature, you are focusing on text on one page that is clearly going to be expanded on in later text and operating as if it is the complete advice.
On the other hand, to directly address your point. A classic dungeon, pre-stocked with rooms with traps and monsters is a completely pre-determined adventure.
The order in which the characters tackle the job of clearing it out is not so predetermined, even if the dungeon is particularly linear as they have non-combat options (or as long as the DM is willing to accommodate alternative ways of tackling the encounter).