Save the event file to your PC and open it with Ór. To do this, Launch Ór. Use the File→Import→Competition menu and select the .or file.
With a very small amount of extra effort, it is possible to produce splits sheets for competitors with GPS recorders that show their routes. As an example, this is my route from Day 3 of the 2007 Shamrock O'Ringen in Cobdubh.
For Championship events, you should use a spreadsheet, such as Excel, to manage your start lists. You can then export the spreadsheet in CSV format and them import that into Ór. You should use this sample from the 2006 Leinster Champs as a template of an Individual event. For a Relay event, use this sample form the 2011 Irish Orienteering Championships. Do not change the layout of the spreadsheet.