You don't have to worry about assembling the gingerbread house at all. On the contrary, if you've followed all the previous steps, it will go smoothly and easily. I just want to remind you to only assemble all the parts after the decoration has thoroughly dried. It would be a great shame if you were to damage your beautiful decoration now.
Before you begin assembly, prepare some pins or toothpicks (you will, of course, remove them in later steps). Place the gingerbread house on a cutting board. This way you'll be able to easily rotate it and also easily move it.
Watch the tutorial video
Tip for you
Make sure the pins or toothpicks you use for temporary support are easy to pull out later. Pins with a colored head are ideal, for example, because they let you see exactly where you've used them to help.