What programs do I need on linux to manage and load songs on a Sansa MP3 player?
That all depends on the player you bought. I have a Creative Zen mp3 player. All I need to do is plug the usb cable into a usb port, the system tells me there is a new device, and asks me what I want to do. I open it with the file manager. I just drag and drop files to and from the player.
It looks like an external drive. That is it.
That said, there are some players that will not work with. ipods for example. So, give it a go, see if your system 'sees' it, and try your file manager.
If that does not work, you will probably have to do some googleing to find out how to connect to it.