I thought the idea was to save stuff in the cloud so it isn't on the phone? Anyway I managed to get it via the browser but when you download a doc to see via your phone it saves it as a zip file. And Apple doesn't seem to have a facility to open zip files....
Using the phone app doesn't mean that the files are stored on your phone. They're still in the cloud, with the app just working like a browser solely dedicated to the task of accessing your cloud files.