Before diving into using Supabase with AWS S3 for storage, make sure you've got these things sorted:

• A Supabase account (Sign up at app.supabase.io).
• An AWS account with an S3 bucket and the right permissions to access it.
• AWS SDK installed in your project. You can get it with:
• npm install AWS-SDK

To get AWS S3 working with Supabase, you'll need to set up an S3 bucket:

• Log into the AWS Console and head over to the S3 service.
• Click on "Create Bucket," give your bucket a unique name, and pick the region you want.
• Set up other options like encryption and bucket versioning based on what you need.
• Finally, click on "Create Bucket."

You'll need access credentials to interact with your S3 bucket. Here's how to get them:

• Find the IAM service in the AWS Console.
• Go to Users and click on "Add User."
• Give the user a name and select "Programmatic access."
• Attach a policy directly and choose "AmazonS3FullAccess."
• Review everything and click on "Create User."
• Download the .CSV file with your access and secret keys.

Now, let's get the AWS SDK set up in your project:

• Import AWS from AWS-SDK in your .JS file.
• Configure the AWS SDK with the region and access credentials you got in step 2.

Here's an example:

const AWS = require('aws-sdk');

AWS.config.update({
  region: 'your-region',
  accessKeyId: 'your-access-key',
  secretAccessKey: 'your-secret-key',
});

With the AWS SDK configured, you can create functions to upload, delete, and retrieve files from your S3 bucket.

Here's an example of an upload function:

const s3 = new AWS.S3();

async function upload(fileName, filePath) {
  const fileContent = fs.readFileSync(filePath);

  const params = {
    Bucket: 'your-bucket-name',
    Key: fileName, 
    Body: fileContent
  };

  try {
    const data = await s3.upload(params).promise();
  } catch (error) {
    console.log('Error while uploading file', error);
  }
}

Once you've got your storage functions ready, you can start using them with Supabase. Whenever something happens in your Supabase database or authentication state, you can call these functions.

Don't forget to add error handlers to make sure your storage operations go smoothly, or to retry them if they fail.

Place the calls to these functions where you handle Supabase events. For instance, to upload a file when a new row is added, you can use the Supabase Realtime module to subscribe to table changes and call the upload function whenever a new row gets added.