To zoom to fit the entire level of your design in Infurnia, you can follow these steps:
Click on the dropdown arrow against the Zoom icon in the Home ribbon.
In the menu that opens, select "Zoom to Fit Entire Level."
Keyboard shortcut: Shift + Z
As per the level selected "Room/ Floor etc" it will show all elements in that level.
This action will adjust the zoom level to fit your entire design level, making it easier to view and work on your entire project without having to manually adjust the zoom.