If customer does not check any check box for Department and Location on the left, the right hand side should show positions for all Departments and all Locations. This may be a very long list so you should design the default display to just show the Department Names only, then customer can click on the Department Name and the section will expand to show all positions in that Department.
Now your display show details of all jobs. If have many jobs, the screen will look messy
Reference Index Living Mall http://www.indexlivingmall.com/career/job-en.php