Maybe we just do it differently here in the U.S., but it's a fairly simple proces, but probably difficult to explain... but I'll give it a try.
Pick up the uncooperative sheet and select one of the "pocket" corners. Place your doubled fist inside of this "pocket. Next, find it's opposite and place the sheet covered fist inside that "pocket" corner. Next, do the same thing with the previously free hand. You should now be standing with two sheet covered fists with two pockets covering each. Place one fist inside the pockets of the other and remove that hand. You'll now have a semi-rectangle with one corner consisting of all pockets and the other three corners with no pockets. Lay the sheet down and simply arrange into a more symmetrical rectangle and fold into desired size. Simple and clear, no? Well, for those of you who are direction taking challenged... look at this:
https://www.youtube.com/watch?v=YHTyH2nuFAw