To run the Pico/Elf V2 emulator at least the Pico/Elf V2 ROM file should be specified in the 'ROM' field (orange ellipse). Default the Pico/Elf ROM location is the Pico directory (located in the application data directory, see Directory and File Structure) and the default filename is 'PicoElfv112.bin'. To change the location use the 'ROM' button (yellow ellipse) to browse for the file, do the same to change the filename or type in a new file name in the text field (orange ellipse):
Note that files in binary format, normally using extension .bin, will be loaded at address hex 8000. Intel hex and RCS Elf emulator hex format include storage locations and as such will be loaded in the specified address location.