ok... Google around for a bootable ADF... then In Hi-Toro goto the HDD tab, and select "Add Directory". Then choose a nice directory on your HD (set it up as DH1: or whatever) :-)
Now boot the Emulator with the ADF, if you are using KS3.0 or better then the Directory you slected on your Mac will now show up as a Hard drive on the Amiga... put the OSS file in the Dir and switch back to the Emu... run... have fun :-)