Is there documentation on how editing one timeline affects another? Sometimes moving or slicing or time stretching a clip splits or moves tracks below it, sometimes not. Sometimes tiny sliver-remnants appear for no apparent reason, etc. I can't figure out why. Is there a way to lock a track in place so other edits don't affect it?
There is no track locking feature in Premiere Elements.
What version of Premiere Elements are you using, and what computer is involved.
There are certain amount of Timeline content maneuvers you can control using keyboard modifiers (Windows, Alt or Ctl key). You can apply Group to bunches of clips to keep them together.
This older thread may be helpful Premiere Elements: Arranging clips on the Timeline using modifier keys | lynda.com - YouTube
I am posting it for informational rather than promotional purposes.
Also, please look at the following Adobe document on adding files to the Timeline.
Please consider, supply more details, and let us know if you need supplemental information.
Thanks, I will look at the tutorials.