Hi Victoria
Welcome to @BanjoBen 's Forum. As Mark points out what you are hearing in the bottom three Mp3 is what the Rhythm Guitar plays whist you play banjo. It takes a bit of time to get used to playing with the Guitar Backing Track, One thing that really helped me was TablEdit (or you can use the Free version TefView) Download the .tef files to your computer and you will be able to see the Banjo and Guitar TABs on different layers.
Here is a Tutorial on the use of TablEdit. Towards the end of the video at 4.26 Ben explains a little bit about the layers that house the lead and the backing tracks. How to toggle off the lead track so you can watch the TAB and practice whist listening to the backing track. In this tutorial Ben has used a Guitar lesson but the same applies to a banjo lesson. Hope this helps Victoria. Good Luck
https://www.youtube.com/watch?v=tzS9NxVuNbg