title: Intellij IDEA: How to add single class file to project
body: <p>I have a very stupid question. Installing IDEA I want to create a very simple two files project (two java classes), one of which I already have. So I started empty project, created my new class file (I have only one top directory with this file) but I can't attach second to it. 
  Earlier I used notepad and terminal for such simple porpuses and it was enough to copy file to "project" directory. Can someone explaine how can I link two class files in Intellij IDEA? </p>