Somewhere in this Parsha we move from year two in the Midbar to year forty. This means that there are thirty-five plus years that are virtually silent and unrecorded in the story of Bamidbar. This does not mean that nothing happened during this time. It just means that the Torah does not relate every detail of every year during this period.
In Bereishit, we cover twenty generations in a matter of a couple of Parshiot, whereas the forty years in the Midbar take up quite a lot of space in the Chumash.
One should not look at the Chumash as (only) a book of history, but as a book of teaching and guidance. The Torah relates laws and narratives that are there for a specific learning purpose. Our job is to figure out what each verse is teaching us.
That task takes far longer than forty years!