Okay kiddo, let's pretend you have a piece of paper with a big X and a big Y drawn on it. That is called a coordinate system.
Now, imagine we want to move that X and Y around the paper without changing anything else. That's called translating the axes.
So, let's say we move the X to the right by 3 inches and the Y upwards by 2 inches. The coordinate system will still be the same, but now the X and Y will be in a different position on the paper.
Why do we do this? Well, sometimes it can make it easier to plot points on the coordinate system or to see patterns in the data we are analyzing.
But don't worry too much about the why right now. Just remember that translating the axes means moving the X and Y around without changing anything else on the paper.