I agree - that looks far too complicated. I wash (and iron!) the duvet covers and pillow slips inside out (done up, so no knickers worm their way inside), undoing the buttons whilst ironing. Hang the duvet over the banisters, put arms in to top corners, hold the corners of the duvet and drop the lot over the banisters. Lay it on the bed, do up zip, buttons, poppers or whatever. (That's the most tedious part) Simples.
Now, we have a king size duvet, which, as far as I can see, should be 220 x 210 cm. I'm blowed if I can work out which is the longer side. I always have a bit of duvet cover which isn't filled. I have tried folding diagonally and following the sides along to see which is the longer of the two, and then doing the same for the cover, but it foxes me every time. Why can't they just be 220 x 220 then there'd be no confusion.