Hold on....
Workbench 3.1 does boot but comes up in a CLI window, which is normal. It will not boot to workbench (funny enough) at least mine (from Amiga Technologies) doesn't.
To install Workbench on your hard drive you need Install 3.1 (your workbench set should be 6 disk total, Workbench, Extras, Locale, Fonts, Storage and Install).
If you boot from Install 3.1 you will boot to a Workbench environment with the option to install the hard drive.