First, you can still base a report on a query. Design the query and save it, then select it as the source when you define records, tableframes, etc... on the report.
Second, if you open a report in design mode, you can click on a field and select 'define field'. This will open the field definition dialog box. If they used the 'expert' to make the report, then the table name will be the alias 'MASTER' by default, otherwise the name of the table(s) will be in the dialog box. To determine the true name of a table that is behind the MASTER alias, simply open the data modeller (the little button at the top left that looks like two folders offset) and you will see the table represented.