Making a Window

One way of making a window is by using the present ones in the create panel and simply fit it into the place where the window will go. The second way is to start off with a box and turn it into a editable poly. From there, select the front and back polygons and the inset to the desired size of the frames and then extrude the faces inwards depending how deep the frames will be. Once that is done, depending whether 1 or 2 panes of glass is desired, delete one of the panes and then bridge the gaps.