All you should need to do is fire up the driver by double clicking on it in, or putting it in the devs/dosdrivers drawer.. PC0: for DF0:
Then insert a 720K formatted IBM disk and it should come up.
If not, something else is wrong.
Ohh BTW if you want to format a 720K disk in Windows use this command : format a: /t:80 /n:9
Don't forget to cover the HD Tab !!!