It sounds like you're experiencing timeline rippling.
The way to override rippling is to hold down the Ctrl key as you add and move clips on your timeline.
You can also get a basic understanding of the program with my free Basic Training tutorials at Premiere Elements support site Muvipix.com.
And, if you want to thoroughly understand the program, my step-by-step books are available on Amazon.com and at Muvipix.com.
Thanks, I´ll try...
Also, one can Select, say just the Audio portion of a muxed Clip (one that contains both Audio & Video, i.e. Multiplexed) with the Alt+click.
When working with a Soundtrack, a great feature would be Track Locking, like with PrPro, so that specific Tracks can be Locked, and hence not edited. I have filed Feature Requests, but urge you to do so, as well, since Adobe uses the number of such requests, when developing new versions.
Good luck, and Steve"s suggestions are really good ones. This ARTICLE will give you links to his mentioned resources, plus some more.
Good luck, and happy editing,