I'm new to freecad, so far I made it this way :
Sketch a rectangle for the top surface, pad it, add filets for the corners. Then select to bottom face, make a new sketch, another rectangle, then a datum plane 40mm below, sketch another smaller rectangle, and make a loft between the two to create the bottom of the tray.
Now for the hole I made a rectangle on the top face and made a pocket with an angle.
Downside of this, the thickness of the walls is not equal. Ideally I'd like a 1.5mm thickness everywhere. And I'm not really sure how to proceed to make the separators inside the tray.
What is the most efficient way to do it? thanks
In this case as a loft. Not say that's necessarily the right way to do it, but that's how I'd do it. See my other comment on the matter here.