Measure the width of the windows.
Cut pieces of cardboard to fit between the window frames. Tip: it doesn't have to be from 1 piece of cardboard, you can feel free to make it from several pieces.
Using the ruler, draw shapes of houses on the cardboard. Take the width of the window frames into account if necessary. For example, I left a seven-centimetre border empty at the bottom so that they could stand on the windowsill, and I could clip them behind the curtains. Tip: make the houses of different widths and heights.
Cut out the houses. Use your cutting mat and ruler. If you don't have them, you could also do it with good scissors.
Then use your pencil and ruler to draw doors and houses. Again, in different sizes.
Cut out the windows and doors.
Decorate the edges of the roofs and windows and doors with the white (posca) marker. Tip: vary with curves, dots, dashes, draw roof tiles, stones, snow edges, hearts, etc. Search “gingerbread houses” on Pinterest, for example, for inspiration.
Place the houses behind your windows. You can secure them with some double-sided tape or pieces of painter's tape. (In my case, they are stuck between the window frame and the curtain). Tip: use a light string behind the houses for extra atmosphere!