Help Creating the Shanghai World Financial Center

So I’m obsessed with the Shanghai World Financial and want to build my own model of it. The building is 1,614ft tall and has a trapezoidal hole cut out of it at the top. It is both curvy and smooth but simultaneously sharp-edged and robust, which in my personal opinion makes it one of the most beautiful skyscrapers in the world. I will add further details to the model but I’m new to sketchup and am having trouble creating the basic shape. I’ve found several tutorials on Youtube but none of which are available in sketchup. I’m still learning the sketchup interface and can create basic buildings with simple fixtures, but with the unique and complex shape of the building, I really don’t know where to start or what plugins to use. Does anybody know the simplest way to create the basic shape for the building? Also what plugins will be most useful for creating similar shapes.

Learn the basics of SketchUp - SketchUp Fundamentals -Part 1
Look at the tutorial you gave as example, it’s well done.