Where do I see the discounts my cashiers gave away this week?

On the Z reports. Open Reports → Shifts and the POS, pick the dates, and open each shift: the Z report lists discounts given for that shift, next to refunds, cancelled after printing and what each way of paying took. Every discount at the counter needed a manager and a reason, and the reason stays on the sale, so Find a sale on the POS shows who gave what and why. Online, the Coupons & promos panel on your Dashboard shows which codes were used and what they cost you. The two are kept apart because a coupon a customer typed and a discount a manager approved are different questions.