Amazon ec2: how to start using Reserved Instance?

Question

Amazon Web Services

Bought Small Heavy Utilization Reserved Instances for $276.
After that, I launched a small instance from the same time zone from which I bought Reserved Instances.
A month has passed, the money was taken from a credit card, and not from Reserved Instances.

Maybe someone faced such a problem, how to make it so that the money would be withdrawn from the already purchased Heavy Utilization Reserved Instances?

Answer 1

Money is always withdrawn from a credit card, reserved instance is a discount.
Read carefully my article about the types of instances, I explained everything with pictures there.
habrahabr.ru/blogs/cloud_computing/136829/