So, imagine you have a bunch of toys that you want to sell. You could sell them to your friends or family, but what if you want to sell them to someone who you don't know?
That's where an alternative trading system comes in. It's like a big playground where lots of people can come together to buy and sell things without needing to know each other.
Instead of selling your toys one by one to different people, you can put them all up for sale in this playground and lots of people can see them and buy them if they want to.
But you might be wondering, "How do I make sure I don't get ripped off?" Good question! The people who run the playground have rules to make sure everyone plays fair. They also keep track of all the transactions that happen, so if there's a problem, they can help fix it.
So there you have it, an alternative trading system is like a playground where lots of people can come together to buy and sell things fairly and safely without needing to know each other beforehand.