Shimano front derailleur - tensioning, can't move shifter
Best approach is to start from scratch following a procedure so you know you are not making things worse. 

There are a few youtube videos that walk you through the procedure. My favorite is Park Tool Company’s as it’s the easiest to follow and includes checking height and yaw. (Link at bottom.) 

Before attempting the adjustment, make sure the cable and housing is properly inserted into the shifter body and and the guides on the frame. 

Another thing to do is check the shifter is pulling the cable properly, and the cable is running freely independent of the derailleur. Disconnect the cable from the derailleur, grab the cable and put some tension on it (a set of pliers can be helpful), then turn the front shifter through it's clicks. You should feel the cable retracted and released.

Front derailleur and shifting adjustment is pretty tricky, so don’t feel bad that this has got the better of you.