I am an international student.
I filled up the online CSS Profile and also filled up the separate form for Princeton.
** Do I need to do anything more? Do I need to courier any hard copies? **
Also, one of my universities said they want an IDOC which tried to fill up. The problem is, I couldn’t figure out which documents must be sent by internationals and which by nationals. There is no separate portal for internationals alone. It seems combined for all nationalities.
** So, what is an IDOC? What documents will I have to put there? **
I know that I could contact CB or the university and inquire but considering the exorbitant rates in my country to make an international call, I thought I’ll ask here 
And yes, I tried checking on the net, but it’s pretty obscure. Most of the information is for US Nationals and I had a quite difficult time sorting out the information.