Because you have a kickstart rom switcher you can run Workbench 1.3 or Workbench 2 and Workbench 2.1. You do need a copy of Workbench on floppy disk to load it. There is no other way.

Sometimes copies of Workbench are sold on Ebay and other sites, so keep an eye out.

To convert adf's back to real Amiga floppy disks there are a number of methods. The easiest is a commercial program by Cloanto called Amiga Explorer. You can connect the Amiga to the PC using a Null Modem cable (connects to the serial ports on each machine) and you can access the Amiga from the PC program and easily convert ADFs from the PC directly to the Amiga's floppy drive.

Alternatively you can also use a number of different free ADF to Disk programs, but you need to get the ADF onto the Amiga first, which is hard without a HD in the Amiga, or less than 2MB of ram.