Here is a quick document that I have made just using the layout options to show an overlay when you go to landscape mode. I would also make sure the viewport width is set to device width (in the Document inspector)
forceOrientation.hype.zip (59.1 KB)
You will be able to grasp it as it’s quite basic.
Creating a layout (I chose iPad because these are preset in Hype) I created 2 layouts (Portrait and Landscape) The portrait one I place the content I want users to see (I put this in a persistent symbol so I wouldn’t have to copy and paste. If I change in one it auto updates in the other. Across scenes too)
I then did a quick animation on the landscape one with elements above the rest so that it overlays them. Thus stopping any clicks, etc. This animation will play automatically on device rotation. (Main Timeline runs on layout / scene load) user can do nothing but follow the crude message to turn back. He then gets the portrait mode where he can carry on. I have added another scene (duplication) so you can see the same approach is copied and I just added a few extra message and changed the message on the overlay.
Hope this helps!