Well, you need a Amiga 1200 (or any other Amiga wich can have the roms in it you want to grab) and then have the roms in it, then boot with a bootable Amiga disk with transrom (comes with the emulator) and run the program that will write the image to a file on the disk.
But you need to run crossdos to write it to a "pc" (yuk) floppy.
Can you get a copy from someone else if you have the roms yourself but cannot get the romfile? Anyone?
Coder