Transom window installation depends on the height of the door and ceiling, whether the wall is interior or exterior, how much it weighs, etc.
The standard procedure for installing this window is to remove the drywall and exterior cladding above the door. It will then have to remove a portion of the wall studs to reframe the section.
Once the window is set new drywall has to be installed. Remove the exterior cladding if the wall is exterior. Finally, the window trim has to be installed.
It is very important to make sure that the transom window will fit the house structurally.
A ceiling higher than eight feet is more suitable for this window. However, window models with non-load-bearing internal partitions can fit on the door in the wall.
When buying a new transom window it is important to read the installation specs carefully to determine the rough-in framing for a particular window model.
If there is no concept of standard house framing then an experienced person should be consulted to choose a transom window for that wall and if the wall is load-bearing then this matter is very necessary.
This is important because the entire wall section has to be opened to change the framing and add additional structural support.