To create a business owner go to your dashboard and click on "more" tab, then in the "users" window click on "Add" to create it.
Once you created a business owner to assign to a store you need to go to your stores and click on edit to the store you want to assign the business owner.
Now, in "General Information" window, scroll down to find the Business Owner field.
Just select one of the created business owner and click on "Save and Continue"
Now you have assigned a business owner to a store.
Glad we can help
Have a nice Ordering
Regards, Pol Zepeda