Only Office 2010 or Office 2007 for Windows will work with Office 365. Compatible Mac OS versions are Office for Mac 2011 SP1 and Office 2008 for Mac with update 12.2.9 or later. Earlier versions of Office will not connect with Office 365. Office 2008 for Mac 12.2.9 also will need Microsoft Entourage 2008 for Mac, Web Services Edition.
Assuming the target computer meets the requirements for Office 365, it also will need Microsoft Lync. We set up our test machine by signing into the Office 365 portal and selecting Office 365 Settings from the "gear" menu in the upper-right corner. Select Desktop Setup and follow the prompts. This will install the .Net 3.5 Framework and other plumbing to connect desktop apps to their cloud-based counterparts. You also can install Lync and Office apps from there. The process was easy and only took about 10 minutes, but it's manual for each client.