The Files screen shows all the files that have been recorded.
The (D) files are data (.csv), and the (A) files are audio (.mp4).
If you allow Google Drive integration, you can upload files to your Google Drive.
You can select a single file by tapping it. Tap it again to de-select it.
When selected you can Open, Upload to Drive, or Delete the file.
To open a file, you'll need to download an app that can open that file type.
A good app to open audio files is Files By Google
The data (.csv) files are best opened in Google Drive as a spreadsheet file.
To select more than one file, press and hold a file. This will switch into multi-select mode.
Check the box next to files to open, upload or delete.
Warning: Deleting a file is permanent!