Many philosophers of physics assume The Past Hypothesis, that the universe was extremely low entropy compared to today at the Big Bang, "over and above" (Harvey S. Brown) the laws of physics.
With unitary and symmetric laws of physics, the Big Bang is a necessary prior/initial condition to pick out a direction of time, e.g. the second law.
I say all this because this prior/initial condition is what stands in for the director in your analogy. Instead of director creating a reel of film to set in motion, it is initial conditions + physical laws of evolution that predicts rather than creates one frame to the next. And with symmetric and unitary laws of physics, any frame predicts its adjoining frames in either direction.
For the "setting in motion" part, the B-theorist has to say the feeling of time flowing is a subjective illusion. It's not that this flow of time, this subjective illusion in the brain, is unphysical or dualistic necessarily. Rather it has the same status as any other subjective experience, like colors, warmth, and pain. And B-theorists often say subjective experiences like these will be explained in time by neuroscientists and psychologists.
Why set it up this way instead of just having an objective flow of time? Because the laws of physics are completely symmetric. Thus we have to posit this extra Past Hypothesis to explain why world looks like it does today. So either the laws of physics are wrong/incomplete, or the laws are pretty accurate and it's the initial condition we have to explain.
Finally I can now say, from this block perspective of the laws, there is no privileged present. There is not even a privileged past or future. The Big Bang is just a prior condition, not necessarily an initial one. This equity of the laws, that any "frame" predicts and other frame is very attractive.
So as far as evolution, all we are committed to admitting is that prior conditions were such that together with the laws of physics predicted/created a branching structure of complexity of life. No extra extra commitments to a director, creator, theology, etc. We can happily predict backwards and forwards (within the laws' limits) to our hearts contents. Maybe that's all we can ask of science.
A final analogy from Harvey Brown might help. The laws of physics determine/predict one patch of spacetime to the next in any "direction". This situation is like a patterned rug, where one patch of the rug predicts the patches around it. No objective flow of time, no "creation", just predictions about patches. The psychological flow of time has to be be explained to complete the story, but many are optimistic.
Hopefully all this shows how a B-theorist might hang things together. Creatures evolved later (like us) really just "coexist" with all the other past creatures. There is no privileged present or slice of spacetime. (Again, physicalist minded B-theorists admit the further task of explaining conscious experiences including flow of time, but which philosophy doesn't have to ultimately explain conscious experience at some point).