This kit is very easy to build together and does not require any step by step instructions. First you stick the windows on the roof and the front with wood glue (I use Ponal Express). On the back of the front, glue a small bar on the recesses for the door. Make sure that no glue gets into the recesses so that the door can be opened later. If the strips are dry and firm, you can use the doors and glue the door frame onto the front. Here, too, make sure that the doors do not glue. If you keep the frame and door, you can paint the box, stick it with wallpaper. Especially you should design the inside before you glue the box together. Then stick the box together and insert the roof. You can leave the front open first to be able to design the interior better. Finally, you paint the front and put it in place.
Have fun decorating. If questions are still open, write me here in the comments or by mail.