Walking is acceptable on newly formed concrete only after 24 hours have passed since it was poured. Even then, walking on the concrete before 48 hours has passed can still cause scuffing and marks on the surface.
Although concrete is safe to walk on after 48 hours due to the hardness level achieved, you should still avoid making sharp turns or skidding on the surface for the first seven days after pouring. Skateboards, bikes and toys are also not usable on the concrete during this period.
After seven days, the concrete surface can be freely moved upon, whether you're walking over it or driving a light vehicle. When driving at this point, avoid the edges of the concrete because they are not as strong as center points. After 30 days, the concrete is usually fully cured and can be used as normal.