Copy items from one project to another is accomplished using the mouse right-click and choosing Migrate. Once the window open to choose the destination project you need to choose the Content folder of the destination project . is the best method of copying, since it will also migrate the dependencies. However, has a C++ plugin that you will need to copy manually. I have posted in previous comments, the step-by-step for creating a new project, since it includes the plugin copy procedure.
PS: When migrating, you can do it on the folder level and it will also do on all items inside that folder.