I initially start a project which I want to emerge with existing project, I have noticed there is a way that you can add a project in your workspace, that makes sense, but if I want to use the files of the new project to existing project without dragging and dropping into the bundle, but rather linking it, is there any easier way to do that?
Thanks.
You have several options:
1) Drag & Drop files from one project to the other but without copying them (make sure the 'copy' checkmark is unchecked when importing the files in your project). This will simply link them and editing them on one project will, of course, have the changes to be reflected in the other project.
2) If you're using a version control system like Git or SVN you can link repositories with each other. For example, in Git you can have your main project and link other repositories to it as Git Submodules. This allows you to checkout the changes from all of your submodules anytime they get updated and it also allows you to simply modify the files in your submodules and commit them to the original repository.
There are more ways in which you can accomplish what you want, it just depends on your needs.