I created a discount code for donors to use during registration, but I also have optional upsells included. Will the discount affect the total amount (including upsell), or only the registration fee?
No, the discount code is linked only to the participant types, which can be associated in step 9. Manage Discounts of the TeamRaiser configuration. If there are upsells, such as T-shirts or other items, then that amount will not be affected regardless of the percentage of the discount or fixed amount.