in which situation would you use these three lenses?
Well, best to use them on a camera.
Luckily, you have one, haven't you?
More seriously, I would consider on one hand the 2 zooms for general needs when there is enough light (zooming is a big advantage in composition, because you can manage your image by
both moving your feet to change the perspective and object relationship
and zooming to change framing), and keep the 35/1.8 for low-light situations or shots where you do need the narrow depth of field (portraits).