Hopefully this is not too late. This is not a good link for the technical aspect but, for many common users that are not really familiar with the difference I suggest it.
https://support.microsoft.com/en-us/training
The link will allow them to get a good general overview of what office 365 is and entails. If you are moving a large organization, I would print some of the documentation and leave it in departments as part of the adoption and communication plan.
@mi_davies
