HELP: Editing only one track?

I have been working on editing a song that I have on my iTunes library so it sounds like it’s raining. I had successfully added in the rain loop and saved it, but as soon as I go to continue with adding in the thunder loop, I go to move it to the parts I want it and it moves my whole work. I’ve tried looking at every help guide there is and none is asking the question that I am.
Here’s a link to a picture of what I am trying to do (in case I was not very good at explaining)
I have tried selecting none, copying/pasting, using the time shift tool, the selection tool, and all of them ended up with the top audio that I want to keep being moved around and deleted.
Help as soon as possible would be very much appreciated.

Turn off Tracks > Sync-Lock Tracks. The little “clock” symbol in the tracks shows that you have that turned on. It is not on by default.