
The man working is a carpenter and is working by the emergency light because the lights in the building have not been turned on yet.

This is the view of a window from the interior, the weather proofing that is nailed to the exterior is pulled through the rough opening before the prefabricated window is installed. The main frame is made up of the head, the side jambs and the sill. The sash is the window frame that holds the panes of glass, it is made up of the horizontal members -rails, and vertical members -stiles. Connecting the panes of glass are the muntins. This is an awning window and its operator is on the bottom, resting on the sill.
We can also see the interior framing of the wall and the window. The wall studs are running vertically, butted against the window are the jack studs and next in line are the kingstuds. Under the window are the cripple studs, all the studs are sitting atop the bottom plate.