A code snippet to download files from S3 by providing rootbucket, access key and secret key.
AmazonS3 _client;
using (_client = Amazon.AWSClientFactory.CreateAmazonS3Client(accesskey, secretkey))
{
var util = new TransferUtility(_client);
var request = new TransferUtilityDownloadRequest()
.WithBucketName(rootbucket)
//e.g. full path is sohail/video/123.mp4
// root bucket is sohail, video/123.mp4 is WithKey
.WithKey(at which location have to download S3 file)
// Where to download location of hard disk.
.WithFilePath(ToDownloadPath);
util.Download(request);
}