We can talk about the fundamental difference between socialism and fascism (fascism and nazism are capitalist societies in their economic basis—private ownership of the means of production. Under fascism/nazism, private property is firmly in the hands of capitalists, and large capitalists and monopolists at that. But this will probably be incomprehensible to you. So I will give an example that even children will understand.
Here we have two representatives of the animal world, which moreover belong to the same biological class. They are a wolf and a sheepdog. They are very similar in size, they have similar fur, claws, and fangs, they are both predators, and they both eat meat.
But the wolf will hunt your livestock and, if possible, kill all your domestic animals, even if it does not need to eat them. It will even kill you.
And the sheepdog. It is your friend, helping you run your farm and giving its life to protect you...
Very similar living creatures, yet how different they are in their attitude towards you.
But what matters to you is how they look, doesn't it?