transferring pages documents to and from iCloud

Hi, I elcappitan, latest version and pages update. I have a book that I am writing with multiple chapters, and want to use iCloud essentially as a storage and backup, not that is to work in iCloud itself. If I drag a current folder to iCloud I think I have to press option to get it to copy it, and not transfer it. Getting it to then download that current version onto another device, I think I have to press option again, but when I try this it looks like some of my data has been lost. - Does it somehow decide that my second device already has some identical chapters of the folder? I guess the idea is that I'm supposed to work in iCloud itself, but then what if the internet goes out (as it not infrequently does where I work)? - I guess I would like some clarification as to how iCloud handles folders with Pages data in them beyond what I can find in the support documents - Thanks, Ray