When we look at a map, it shows us the different places in the world. Normally, most maps show the north at the top and the south at the bottom. But sometimes, we can look at a map where the south is at the top and the north is at the bottom. This is called a south-up map orientation.
Think of it like this - imagine you have a picture of a butterfly. If you turn the picture upside down, the butterfly is now on its head, and its wings pointing downwards. Similarly, when we turn a map upside down, now the countries that were at the bottom are now at the top, and the countries that were at the top are now at the bottom.
Some people like south-up maps because it gives them a different perspective on the world. It can also be useful when we are studying things like the southern hemisphere or the south polar region.
In the end, it doesn't matter whether a map has a north-up or a south-up orientation. What's important is that we use the map to learn about the different places in the world and understand how they fit together.