Okay kiddo, so you know how sometimes countries don't get along with each other, and they might even fight with each other? Well, some countries that are friends with each other decide to help each other out when one of them is having trouble with another country.
That's where the free world military assistance forces come in. They are a group of military people from different countries that are friends with each other, and they work together to help out other countries when they need it.
So let's say one country is having a really hard time fighting off some bad guys, and they ask their friends for help. The free world military assistance forces might send some soldiers over to help fight with them, or they might send supplies or equipment to help out.
The idea is that when countries work together, they can be stronger and better prepared for anything that might happen. And the free world military assistance forces are a way for countries to show that they care about each other and are willing to help out when things get tough.