I have several board projects that I want to put in one single board.
Can I just copy/paste each project for a new one? Do I have to export the .dxf file from each board and than import them to the new one?
The purpose is to send this new project to the PCB factory so I can reduce costs by sending one board instead of four.
I guess you are using Ultiboard. Maybe by going to File>Import>DXF , you could merge your boards into one project.