Is there a way to load a file from an Amazon S3 bucket?

Yes, there is.

First, go to the Data Sources page and select your S3 data source.

On the S3 data source configuration page, provide your relevant S3 address (the bucket and path to the folder/files you wish to extract) and credentials (AWS Secret Key and Access Secret). Then, click Next to authenticate.

Once authenticated, a list of files from the address appears. Choose the ones you need to import or select all of them by checking the All checkbox.

Finally, fill in the Destination field for the name of your destination table. You should now be able to collect the data from the source.

Note: If you select the All option, it will load only the modified (new or updated) files since the last successful collection. You can read more about it in Panoply's documentation for the Amazon S3 data source.