There are operator instruction manuals available online.  Some sites offer free PDF files and Ebay has some reprints for a small price. Also a fellow, Ted Munk, has an operator's manual and service manual in one book  for sale at an internet site I think is Lulu. Search for Reverend Munk or Ted Munk. I got one and it is extremely helpful with some of the repairs on mine.   The touch control has more to do with key action resistance for the typist than key strike on the platen although they can be related. Of course pounding on the keys will give heavy impressions no matter the setting.  If you find yourself tiring from stiffness of the keys then a light setting is in order.  If your hands are strong and you find the action too light with heavy strikes on the platen, then choose a higher number for firmer key action. There are 8 settings.  I myself like a 3 or 4.  It's all about what makes it usable for a typist to last a full day at work and few typing errors