When you import people and/or sources into Clooz using the Data Transfer Manager, you are simply importing the individual people (which Clooz then remembers who they are in the other program), or in the source case, the individual source. No events are imported, since Clooz is entirely document-based. It is the events (or characteristics) in your family tree program that link a person to a source. Thus, there is no real way to reproduce that link in Clooz.
However, when you export a document from Clooz back to the family tree program, Clooz will exact information from the document and produce a list of events. These will be automatically linked to the source of the document in order to have the event in the family tree program proper cite the source.
Think of it this way… You can create a birth event based on information in a birth certificate, however, you cannot create a birth certificate based on a birth event. Clooz is dealing with the documents, which becomes evidence of events occurring. It is not a substitute for your family tree program.
In Clooz 4 there is a new feature to help meet this need. When you import people who have events which cite sources, the source record can be imported automatically and research tasks can be established to provide a list of the sources that should be reviewed for you to generate Information Records in Clooz. You would still need to determine what information a particular source really provided regarding that person’s events, but this is an organized way to step through that process.