In the Authenticate User server behavior you should be storing the UserID in a session variable.
Once you have done this on any page that a user is viewing records that you would like to restrict to only that user you could do so by filtering the recordset.
All you have to do is edit the recordset in DW, at the bottom of the interface is the filter options. Just select to filter on the UserID column and specify a session variable and put in the name for your session variable that holds the UserID.