This is the method by which you can see and interact with drawing files that exist outside of the drawing you are working on. This method of working has many advantages, but you do need to set up correctly for it to be worthwhile. It also relies on all of your collaborators buying-in to the process.
It is possible to import many different types of files into Vectorworks and the various Import Commands can be found in the File > Import menu.
Likewise, it is possible to export your work to many different file formats. The Export commands can be found in the File > Export menu.
Keeping resources that you have made or even found elsewhere is one of the reasons people use CAD software. Setting up libraries that you can share across several computers will make this an efficient and productive way to work.