How do queues work?

As shown in the following diagram, SQS works on the put-get-delete paradigm:

Working of SQS

The put-get-delete paradigm works in the following way:

1. The Publishing Application pushes a message, M, into the queue.
2. The Consuming Application pulls the message, M, from the queue and processes it.
3. The Consuming Application confirms to the SQS queue that processing on the message is completed and deletes this message from the SQS queue.