Okay, imagine you have a toy box with lots of toys in it. Some of these toys you play with all the time and really like, but others you hardly ever play with and don't really need. The people who make the model list of essential medicines are like the grown-ups who look at your toy box and decide which toys are really important for you to have and play with all the time.
But instead of toys, the model list of essential medicines is like a list of medicines that are really important for people to have access to all around the world. These medicines are chosen because they can help with many different health problems and illnesses, and they are considered safe and effective for most people.
The grown-ups who make the model list of essential medicines are actually a group of experts from different countries who work together to look at all the different medicines that are available. They study lots of information about each medicine, like how well it works, how safe it is, and how much it costs. Then they decide which medicines should be on the list of essential medicines that people all around the world can have access to.
So just like how your grown-ups help you decide which toys to keep and which to give away, the people who make the model list of essential medicines help decide which medicines are really important for people to have and use.