And it's that easy:
Which handicraft materials do I need for Windowcolor?
You need a motif template, an underlay (e.g. transparent cover), Windowcolor Contour Liner and Windowcolor colours.
How do I tinker Windowcolor?
Place your motif template under the transparent painting base. Then paint the contours with the Windowcolor Contour Liner and let it dry
Then paint the surfaces in the desired colours. After drying you can now remove your picture and decorate your windows with it.