To make a symbolic link from a file in one subdirectory to a file in another subdirectory:
ln -s reports/reportA publications/my_report
This makes a symbolic link between the file reportA in the subdirectory reports and the filename my_report in the publications subdirectory.
To make a symbolic link to a file in a subdirectory to your current working directory:
ln -s docs/editors/vi.ref .
This makes a symbolic link between the file vi.ref in the subdirectory docs/editors/ to the filename vi.ref in the current working directory.