Communication Services Package provides two samples, the Sample App and the Sample Conference App. The latter is limited to only making Equinox conference calls, doesn't support the Presence and Messaging Services, incoming calls, but implements the Whiteboard Sharing feature. This guide will continue with the Sample App as an example.
These articles will walk you through the information needed for each SDK service and where to get that information...
The following is a recommended list of articles to get you started: