Choose ‘Product’ from the navigation bar at the top.
In the right options menu, deselect the ‘roof’ option.
In the ‘product’ stage, select ‘Roof’ and then ‘Roof Window’. In the bottom panel, select a Roof Window.
Choose the 2D view option at the top of the design window. Insert your Roof Window by clicking on the 2D view of the house. Position it as needed.
Display the roof again (in the right options). If the Roof Window is not visible, increase its elevation and position it in the required location.
Click the 3D view option at the top of the design window. Then change the view to get a side view of the roof window. In the options menu, lower the elevation until the Roof Window is perfectly positioned on the roof.