S3 Browser is a freeware Windows application you can use to upload/download and manage the content you have in your platform. A paid "pro" version exists, that includes additional features and improved performance. You can download it from here.
To use it for uploading and downloading content from your platform, follow these steps:
1. Get your storage credentials
2. Select Accounts and then Add a new account
3. Introduce in the form your Access Key and Secret Access key
4. Select Add new account
5. Connect to the account you have just created and the S3 Browser will show you a message indicating that you are not allowed to get buckets list:
6. Select Yes and and follow the Getting your S3 bucket name guide to get the bucket name for the container you would like to work with (possibly, the same bucket name is used for all your containers). Introduce it in the S3 browser field and select Yes.
7. The containers you have access to are shown in the left pane:
you can browse your files, upload and download them using the icons below: