The steps to create a mannequin Christmas tree are as follows: (1) Start with a mannequin base, which is usually made of wood or metal. (2) Cut branches of evergreen tree (such as pine or fir) to desired length, and arrange them around the mannequin base in a conical shape. (3) Use floral wire to secure the branches in place. (4) Add ornaments and lights to the branches for added decoration. (5) Add a star or angel at the top of the tree for the finishing touch.