Automated Coupons sent with AutomateWoo

I’m trying to get my head around what I need to do to have a 20% coupon, good for only 3 days, automatically sent x days after a completed sale. I have automateWoo installed and understand everything except how to handle the coupon expiring after 3 days. If I set up a normal coupon using the marketing tab of wooCommerce the expiration date will not be dynamic.