Help on Tascam DP-03 porta studio

[Billy T]

Hello, I am wanting to learn how to send a single track from my Tascam dp-03 unit to my computer. I have acquire to the appropriate USB cord for this. Have read through manual and made one backup to my computer system. Yes I see the 3 folders Backup, Utility and Wave. I see a single file has been sent but when I left click to listen to it a message appears indicating my audio player does not recognize this file extension. Must this be converted to a wav file prior to sending backup? Well if so I can not find instructions in the owners manual. I understand back up and restore for this system but should I have exported or imported instead. what am i not understanding here? All I want to do is be able to work on a song with tracks and be able to send to other musicians to hear a project underway. Any help is greatly appreciated. I am operating Windows 10 with its standard audio playback should I upgrade to another