Now in this case I did in frame 01, but my intention is to make in the further progress all this transforming animation by Driven key, so doesn`t really matter in with frame you key, it is just to save the position.

Well in the frame 01 I keyed in the robot pose, and frame 100 in the car pose, so I move it to the middle 50 and posed into a position that looks like it is transforming(with the hand on the ground).

That basically how I did so far.