What version of Premiere Elements is involved and on what computer operating system is it running?
If Mac, then I have no answer for a program that will allow you to do a copy/paste insert between Premiere Elements projects.
If Windows, then you should be able to do that copy/paste insert between Premiere Elements projects, using Premiere Elements
in conjunction with ClipMate. Please refer to the following link
The alternative is to export the project 1 Timeline content to a file saved to the computer hard drive and then import that export from project 1 into project 2 whose project preset has been set to match the properties of the export from project 1.
There are no sequences in Premiere Elements as in Premiere Pro.
Were you thinking of trying to set up several separated and different Timelines in Premiere Elements to work with them all within one project. Each Premiere Elements project can have only one project preset.
Please review and consider and supply more details.