For those who have no idea what a Millennium Falcon is, watch the Star Wars movie franchise. It is the name of the spacecraft piloted by Harrison Ford in the original movie.
As shown in the video, all you need is a square piece of origami paper. The first few steps simply involve 2 diagonal folds to locate the papers center and then 2 horizontal folds towards the center.
The next few steps give the folded paper a house like shape. Finally, after some complex folds the Millennium Falcon is created. Throughout this video, pre-creases are used to make the subsequent folds easier.