the usual modern FH takeback consists of 3 parts:
1.unit turn with racket pointing up and both hands on racket (some will lift the hand a little more after release)
2. drop the racket down in a "reverse C" motion to the PTD position (keep wrist neutral and racket outside) till the racket is about the height of the ball and a little above horizontal. most of that move is by elbow extension
see tolys great graphic
3. getting into the "slot" by opening the lower body while supinating/layin back hand.