it would only take a few minutes to straighten that bent arm using the method steve has posted.
as far as crank hooking up to the handwheel, balancewheel.. it's that finger in the spokes, to release this use a finger on the back side, lift the crank finger upward. it will move out of the spokes. it spring loaded, it may take a bit of pressure..
anyway to straighten the arm just remove the entire unit, you don't need to remove that arm. something solid like a vise, using the flat area as a anvil and a small hammer, again light tapping it will straighten right out..
in the pic it looks like your missing the crank arm lock ?? should have a spring load pin at the two black tabs