You can access the Unit management by opening the DJ-Catalog2 component and clicking on the Units link in the left sidebar.
Once there, you can see the list of available units. By default, we have added the most popular units:
When you are creating or editing the product, you can choose the Unit for it.
Go to DJ-Catalog2 → Products and edit or create a new product. Now, open the "commerce" tab to see the options.
Choose the correct Unit for your product and click save. From now on, the product is available with the chosen Unit.