The lever with the red knob is the on - off switch. It probably needs to be in the center (off) in order to move the back gear knob.
The lever to the left of that is the forward / reverse lever and engages the lead screw. The middle notch is neutral and the lead screw doesn't turn in that position.
The knurled 'handle' sticking out of the left end of the lathe below the spindle is the "high - low" range for the lead screw. You push it in or pull it out depending on what the chart says. When it's out, you should be able to turn it and make the lead screw turn - if the lower lever in front is put into one of the numbered slots. I sometimes have to grab that knurled handle and turn it a little to get the gears in the quick change box to line up so that I can engage one of them.
That 4914 is a little different than my 5914. I don't see the control to change the spindle speed. Mine has a hydraulic variable speed control on top of the headstock.
You should be able to turn the spindle by hand. If the upper lead screw forward / reverse lever is in either the top or bottom notch, the lead screw will turn when the spindle is turned.
On the carriage, you may want to be sure that the longitudinal or cross feed lever isn't engaged, or it may be difficult to turn the spindle / lead screw by hand.
If this is a variable speed lathe, pull the cover off and look (you may need a mirror) at the green coating between the two parts of the lower pulley. The green coating should be intact. If it's missing, it's a lot of extra work to repair that although I did it myself.
