Navigate to the Supplier details and click Edit on the left
Toggle the Redemption Enabled flag and save your changes.
Go back to Edit (yes, a little bit of a chicken-and-egg scenario)\
In the left panel of the Edit screen, at the top, is a section with a button you can click to initialize the Redemption system for this Supplier.
Clicking that button will create a non-inventory, admin-only "product" for this Supplier with the same Name and Code as each of your active Redemption Entries.
