|This document is work in progress|
A project is stored in a file, so technically you can put where ever you want it.
However you should consider using shared resources to enable you to share resources across multiple projects. Then you can avoid overbooking resources even when projects shall run in parallel.
To be able to do this Plan needs the resources to be created in a separate file, and the projects must be put into the same directory,
If you run all projects, you could just store everything in your home directory, e.g: Plan--. -SharedResources.plan
!-Projects--.-<project1>.plan !-<project2>.plan !-etc
If you are a number of project managers that runs different projects that needs to share the same resources, a similar structure should be in a place where all managers have access.
All managers must have read access to the shared resources file, as well as read access to all the projects.