The answer above seems to work.
As far as I can tell, here is how the documents program in icloud works:
Install appropriate software on computer (PC or Mac)
Enable icloud in other devices (in my case, iPhone and iPad2)
Depending on the type of document you wish to upload to icloud, ensure that you have the appropriate Apple program on at least one of your devices (other than your computer). In my case, I was not able to upload MSWord documents until I installed Pages on my iPad2. Once I had installed Pages, I could upload word files to icloud. After I upload the files, they appear on the documents window in Pages, and I can edit them.
Limitations:
It seems that PDF files are not supported in icloud, except that you can download a file to your computer from icloud in PDF format. (I assume this is intended to allow you to take a "snapshot" of the document at a particular point in time.)
So far, I have only been able to create folders in icloud from Pages, using the iPad2. When I try to do the same thing from my computer (PC), it will not allow me to create or manipulate folders.
I am hoping that PDF documents will be supported eventually. I can get them to my iPad2 by emailing them, or through iTunes, but it would save a lot of time if I could simply access them from icloud. I receive a lot of documents from others in PDF format, and it is helpful to be able to review them either on my computer or on my iPad, without having to send them back and forth. As well, it would be nice to be able to annotate them in one place using multiple devices.