Zeno’s paradox(es) say that nothing can get anywhere (such as a person walking across the room and through the door, or Acheles passing the tortoise) because every time it gets half-way there, it still has half-way left, but then there is another half-way from that point, and again ad infinitum.
People have tried various explanations of why we are indeed able to get places despite the paradox, but they usually tend to be over-complicated. For example, resorting to discussion of Planck lengths, 0.9̅ =1, infinite/converging series, calculus, etc.
A much simpler explanation is that for the paradox to work, you must take smaller and smaller steps, each stride has to be half the length of the previous one, so it’s Acheles’ own fault.
To resolve the paradox, simply take steps that are the same length and eventually you’ll get to a point where the remaining distance is less than the length of a stride. (The same applies to other forms of locomotion, wheels still spin at the same speed and have the same radius, wing are still the same size and flap the same, rocket engines still burn the same amount of fuel, etc.)