The equator principles are like rules that banks and financial institutions try to follow when they lend money to big projects that could have a big impact on people and the environment. It's like when your mom gives you money to buy something at the store, she might tell you to be careful with it and only spend it on certain things. The equator principles are kind of like that - the banks want to make sure that the money they lend is used in a good way and doesn't cause harm to people or the world around us.
The banks use 10 rules, or principles, which are based on things like protecting human rights, not polluting the environment, respecting the rights of Indigenous peoples and consulting with local communities. When the banks are considering lending money to a project, like building a big dam or mining for oil, they ask the company to show how they plan to follow these principles.
If the company can show that they have a good plan, then the banks might give them the money they need. But if the company doesn't show that they can follow the equator principles, the banks might decide not to give them any money. This way, the banks can try to make sure that the money they lend is used in a way that is good for both people and the earth.