Here are two YouTube clips that might help you understand long takes and montage a bit more in terms of how they function in narrative.
Notting Hill (1999) “Ain’t No Sunshine” scene long take instead of montage
Student-compiled clips of montage
Want to study a couple of parallel works of these famous directors? Use these opening clips and Giannetti’s mise en scene analysis techniques (along with his “Editing” and “Synthsis: Citizen Kane” chapters) to see the masters–and their teams– at work establishing perspective/point of view, setting, and theme in the opening sequences.