"Creation of a Variation on BigCommerce is currently unsupported"

Ecomdash currently does not support variations within ecomdash for BigCommerce. You will have to create the variation on BigCommerce directly, and then download the listing in. 

• To download listings, navigate to Listings-->Download Listings-->Select BigCommerce-->Click "Submit"

You will be able to manage your inventory levels, but the variation will show up as individual products within your ecomdash inventory management.