You would need to formulate some algorithm that detects motion. What is motion? Any motion? Any difference in the frame? Keep in mind that the Arduino can only store one frame at a time. If you lower the resolution, you could store two frames and compare them, but what would be your definition of “motion”. A significant change in the number of pixels that are on/off between frames?
It’s not a newbie programming project — you’d need to be experienced with programming.