JobRoller, like our other themes, literally uses the functionality within WordPress in order to work, so I'm really not sure this would be very straightforward, particularly if you don't consider yourself very technical ;) You can find information regarding the AppThemes API and other details in the
AppThemes developer center documentation.
If you have an existing website and simply want to use JobRoller with it, then you could always install WordPress in a subdirectory and run JobRoller off that.. this would be the most straightforward solution and something that many of our customers who have existing home pages they wish to keep, do. Thanks.