At the same time, move your elbow outwards. This will rotate your entire hand around finger 3. The thumb will automatically end up over the F. You just have to drop the elbow, and you are actually already playing the F
You mean i should rotate my elbow 90% from being perpendicular to the piano to being parallel to it??? Doesn't this sound something like ridiculous??
The best way to get to grips with TO/TU is to have someone demonstrate it to you, and guide you in the movements. Trying to figure it out from a written description usually does not work.