You have eyes. Your eyes see things. When your eyes move relative to the object you’re looking upon in whatever way, the closer object moves faster than the farther object. That’s the concept of the three dimensions.
The objects your eyes were seeing, perhaps, were on a flat drawing, or a digital photograph seen on your computer or smartphone. When your eye moves relative to the objects, there is no difference in speed of the objects. The concept of two dimensions.
But what about one dimension? In this dimension, your eyes see nothing, because everything is flat; shaped like thread but extremely thinner. It might have length, but that’s all. No width or thickness.
You cannot put time on the third or second dimension. If you were to graph the date of an event on a coordinate plane, there would be only one coordinate point. Not two coordinate points, or three. If you had multiple events happen at the same time, you would not put them side by side on the plane. Technically, all the events that happen at the same time have the same point.