To be more correct, it would be ln -s /actualpath/file_or_filder /actualpath/file_or_folder
and if you are doing it in the system files/folders then sudo ln -s /actualpath/file_or_filder /actualpath/file_or_folder
Via Dolphin drag and drop, you can do it on the places where you have write permissions, your home directory. Just by left click drag and drop you will get this menu:
Root Actions was diminished in functionality and in most cases removed, and firmly discouraged to be used. Most administration tasks use polkit this days.
Maybe this will help you out: