The Material Design 3 guidelines expresses how content should flow with foldable with slight differences compared to a tablet, for example:

https://m3.material.io/foundations/layout/canonical-layouts/list-detail

But you can mostly get away with a standard, two-pane layout as you would a tablet, though the center padding may be off.

You probably want the center 24dp spacer to be where the crease is, but it gets a bit complicated if you want to use a Nav Rail since it'll offset your layout by 80dp. Here is a web based demo of what the configurations can look like.