Re: how to save guides in CC library

@Jane – saving guides to CC Library is not possible.

However saving guides to ordinary InDesign libraries is possible:
(That's no new feature, present since at least InDesign CS4)

1. Select the guides you want to store in the library

2. Create a new library (a *.indl file)

3. Chose "Add Item" in the Library Panel menu

Now you can try to "Migrate Item(s) to CC-Library" from your Library Panel menu.

Or you could try to migrate one single library item (the guides) to a CC-Library, if you use the little CC symbol with the arrow at the bottom of the panel.
But all that would'nt work with guides. Error message: "… objects like guides are not supported."

Here some screenshots from my German UI:

Guides can be stored in a Library:

Here I'm trying to migrate a selected Library item "Guides" to a CC-Library I already named "Guides":

Error message: "… objects like guides are not supported."

Uwe