OS X doesn’t yet support iCloud Drive and won’t until Yosemite is released later this year; however, if you are a Windows user, Apple has released an updated version of iCloud for Windows that fully supports iCloud Drive!
All you have to do is download and install the program from here. Once you sign-in, iCloud Drive will appear in your user folder and in your favorites menu in Windows Explorer.
With iCloud Drive you can directly view and modify files stored in iCloud.
iCloud for Windows also lets you sync with Photo Stream and sync Safari bookmarks with other browsers. If you have Outlook, you can sync iCloud mail, calendars, conteacts, and reminders. However, Windows users are not able to use iCloud Keychain, Notes sync, or Find My iPhone; although you can always sign into iCloud.com to use Find My iPhone and Notes.