How to assign a workflow template to a list

I created a workflow that auto-increments numbers in a field starting from a pre-set value.  I’ve looked everywhere, but I can’t seem to get the workflow assigned to the list.  

Here’s the message I see that makes me believe you may have to intervene:

"Select a workflow to add to this list. If the workflow template you want does not appear, contact your administrator to get it added to your site collection or workspace."

So I think it may need to be added to our workspace?