To integrate S3 with Amazon CloudWatch for monitoring, follow these steps:
Log in to your AWS Management Console.
In the navigation pane, under Services, click on S3.
Select the S3 bucket that you want to monitor.
Click on the Management tab and then click on Metrics.
From the Metrics page, click on the Create alarm button.
In the Create Alarm wizard, specify the metric that you want to monitor. You can choose from various S3 metrics such as the number of objects stored, total bucket size, etc.
Set the threshold for the alarm and configure the actions such as sending notifications or triggering an AWS Lambda function.
Click on Create alarm to finish setting up the monitoring.
Now, Amazon CloudWatch will monitor the specified S3 metric and trigger the alarm if the threshold is breached. You can view the status of the alarms and metrics from the CloudWatch dashboard in your AWS Management Console.