You can extract date components (day of month, day of week, month, year,...) from a parsed date, and set these new columns as features. And, as a target, you keep the "sales" column.
After the model is trained (and deploy in the Flow), you will need to create a new dataset on which you can apply the model. This dataset can have the dates of next year.
You can learn from our webminars: http://www.dataiku.com/resources/webinars/
I hope that helps,
Jeremy, Product Manager at Dataiku