I do not understand the question
Are you using PREMIERE Elements video editing software, or PHOTOSHOP Elements picture editing software?
Above all, what version of Photoshop Elements and/or Premiere Elements are you using?
It sure sounds like you are using Photoshop Elements (photo editor) instead of Premiere Elements (video editor).
If that is the case, then you should be posting in the Adobe Photoshop Elements Forum.
Just putting on my Photoshop Elements hat for the moment....
1. You can duplicate layer in the Layers Palette by dragging it into the Layers Palette's icon named "Create a New Layer"
2. You can highlight the layer to be duplicated and hit Ctrl+J.
There are no layers in Premiere Elements...you deal with video and audio tracks or may filmstrip spaces.
There are copy/paste opportunities in Premiere Elements.
Please supply us with more details of your situation. And, if this is a Photoshop Elements question, please consult
with the Adobe Photoshop Elements Forum.