Do you have any old coverdisks from back in the day? Many of those have enough of a workable Workbench environment to get started with, i.e., boot into a desktop. Otherwise, you'll either have to buy a set of WB 3.1 floppies from someone here or on eBay.
Since you have a working CD drive, have you considered purchasing WB 3.5 OR 3.9? They both come on CD-ROM.
