Let's see if I can help.The census record can be treated as both an event and as a source.
First create the proper census event for the census record, there are different ones for different years.Attached each individual listed in the census to the proper role for the event.If you want the census event to appear in the family journal report for each indiviudual when you check "principal events" then you should make sure each individual had "principal" checked. Also "principal" has to be checked if you want the census event to show in the Individual record window for each individual (otherwise you have to do shift+F8 to see all events for an individual, principal and non-principal).
Now create a source record for the census. You can then attach the source record as evidence (citation) in the proof window to the census event you created and to any other event where you might have information from the census record such as the birth event.Be sure to move the source to the footnote text window in the proof window.This will be a little different depending whether you are using normal or advance editing mode. The result will be the same.
The census will now show as an event for each of the individual and the census source will be reference in the endnotes when printed.
Hope this has helped.
To summarize, a source is the document from which you are extracting information. You create a source record for it.It becomes a citation when you attach it to an event in as evidence in the proof window.Moving it to the footnote text in the proof window will then permit the source (now a citation) to print out as a footnote (endnote).