report question

I have read the documentation for html-reports several time, but i'm still not sure how we do this (in the best possible way). Can anyone give me some more info/examples. I have a object called "DetailLine" This object has lookups to both the "Employee"-object and the"Journal"-object. I want to have a reports that show a head with Employee-Info and lines from the "DetailLine". This reports should filter on a specific "Journal"-object. - Which objects should the report be based on? - How can we do a grouping on detail-lines pr. Employee? - Do we have to create some template-fields in any object? I would prefeered toprint this reports from the journal-object and the reports should have on page pr employee with the detaillines registered for this journal.