The two embedding diagrams show you the first half of the answer: the ship is always in an inertial frame, i.e. in free fall, but the local curvature of spacetime means that it’s “falling” relative to the distant frame of the Universe.
This is basically like the way a body at rest near the Earth or a star will “fall” in a particular direction. The drive (somehow) warps space in front and behind to provide the curvature needed to make the ship fall in the desired direction. Still in free-fall, no acceleration felt, but moving.
There are still two more parts need to make a true FTL drive, though.
First, the drive has to maintain the warped space in front and behind even as the ship moves. That’s done via the same “somehow” that originally created the warped space.
Second, how is this faster than light? Falling objects around the Sun move fast, but not nearly that fast.
This is where the “time” part of spacetime comes in. Consider an object falling into a black hole. An observer outside sees the object moving slower and slower as it falls in. This is because of how space and time stretch between the observer and the object. But the object itself sees itself moving faster and faster, but below the speed of light, toward whatever is at the center of the whole.
The warp drive is somewhat similar (though also different; it’s not a precise analogy). The ship is just falling faster and faster and faster in its local space. The warped space “connects” (a technical term) the local space to the far away one.
The detailed math is fierce, and I don’t understand what the warped part of the space would be like. Perhaps it’s not traversable, which mean you can’t see though it. But the overall structure is flat (I.e. normal) away from the ship and tilted-flat at the ship (to cause the large acceleration, but without any curvature that would cause large tidal forces).