I am unable to locate any ways of adding already downloaded music to my iPod. I am not seeing options to select a device nor do I see any type of Source Pane. I already have music on the iPod that was added a while ago. Due to a computer issue (restored to factory settings), the music is still on the device, but I do not know how I can manage the content. I do get the option of erasing the iPod and olny adding the new music, but I do not wish to do that. The only options I have on the left side of iTunes are Library, Store and Playlists. I have created a playlist, but I do not know what to do with it now.
Also, is there any way to pull up the music currently on the iPod for management?
You can only replace the content of the iPod not add to it. You need to erase and add music, this is due to the fact that you have restored the computer. If you have music on the iPod that you do not have in iTunes then you need to recover that from the backup of your PC.