When I do similar things like this, what I do is layout the data on one page in the report/column so that they can be folded in half. :)
Ok, It sounds like you are running one report and then a second report, turning your paper from end to end while flipping so that the text has the tops on the same edge...
1) Look at the queries you are using for the basis if your reports.
++ ideally you have a primary key that is numeric in both reports that you can use to sort by. One query sorting in descending, the other query ascending.
2) Sub-reports... this might be a bit trickier... however, I would still try as in (1) with the query sort orders.
2a or 3) In the report itself is the "Order By" property in the property pane
2b or 3a) There are also the Group and Sort properties that could be set by adding a sort (open the report in design view, in an area not on the design section where you place the controls, right-click, in the quick menu select groups and sorting. .. in a sub report it might be best to open the actual object and do this there) add a sort and select the proper fields for the sorting.
clear as mud?
This is really like trying to write instructions for tying ones shoes! :)