How to provide a user to access only a particular bucket in AWS S3?
Amazon's IAM roles generally grant a role access to a particular ARN (Amazon Resource Name). Amazon notes on their pages that for S3 a resource


  ...can be a bucket-name or a bucket-name/object-key.


They also provide a helpful example for doing just this which appears as follows:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": ["s3:ListBucket"],
      "Resource": ["arn:aws:s3:::test"]
    },
    {
      "Effect": "Allow",
      "Action": [
        "s3:PutObject",
        "s3:GetObject",
        "s3:DeleteObject"
      ],
      "Resource": ["arn:aws:s3:::test/*"]
    }
  ]
}