1. One conflict/resolution leads to another.
In Harry Potter, particularly books 1 & 2, the overarching conflict is unraveling a mystery, (What is hidden in the castle? Who opened the Chamber?). Within this larger conflict, the characters engage and complete numerous smaller steps, some planned, while others are unexpected. As they progress, each resolution leads to the next step in the plot.
Some stories are told from a single perspective, in a single location, over a short span of time (for example, Emperor’s Soul by Brandon Sanderson), but in general, the longer a story is, the more complex it becomes. Most novels feature between 2 and 6 different point of view characters, each with their own cast of supporting characters. They engage multiple narrative threads, spanning a wide range of locations and moments in time.