This article tries to give an overview of how some of the high level parts the promotion system works.

For a detailed explanation of every promotion option, see this link.
To see some examples of how to create some common promotions, see this link.
To use promotions together with subscriptions, see this link.

Create and modify promotions

You can create and modify promotion by visiting the promotions page. It's located under Settings > Promotions. Here you will see a list of all active promotions. To see disabled or inactive promotions, select another tab at the top of the page.

To create a new promotions, click the New Promotion button in the top right corner. A popup will appear where you can set all options for your new promotion. Click the Save button at the bottom of the popup to save your changes.
To modify an existing promotion, click the row with the promotion. A popup will appear where you can modify all the options of the promotion. Click the Save button at the bottom of the popup to save your changes.
To disable an existing promotion, either press the disable button in the row of the promotion you want to disable, or open the popup to modify the promotion and click the Disable button at the bottom of the popup.

Here you can find some example of common promotions and how to set them up.

Promotion Types

In SMRT there are two types of promotions:

Promotions that are applied to customers. Every time an order is created for a customer with an attached promotion, the promotion will apply to the created order. These promotions are referred to as Customer Discounts.
Promotions that are applied to orders. These promotions are referred to as Coupons.

A promotion can be both a coupon and a customer discount, allowing you to apply it to both orders and customers.

Note that a customer discount can have a barcode/coupon code as well, allowing you to distribute a promo code for your customers to use.

Marked in red you see where you select what types the promotion is applicable as

Discount Effects

To decide what items on an order are affected by a promotion the SMRT uses Discount Effects. A Discount Effect allows you to control:

The type of effect, i.e. is it a percentage off, a dollar amount off, or will the items will be offered at a fixed price.
Whether or not alterations and surcharges should be affected.
If the discounted amount or number of items should be limited.
What specific items or sets of items should be discounted.

A single promotion can have multiple effects affecting different items. The way it works is that the promotion first tries to discount as many items as it can using the first (the leftmost tab) discount effect. Then it moves on to the next discount effect and tries to discount as many items as it can using that discount effect. An item cannot be discounted by more than one discount effect.

Activation requirements and overrides

You can use Activation Requirements to set conditions on when the promotion will apply to/affect an order. By default no Activation Requirements are set, which is fine for most promotions.

A promotion with Activation Requirements defined will only be applied to the order if all the Activation Requirements are fulfilled. In some scenarios it will still be attached to the order even if the requirements are unmet, but it will have no affect on the price (i.e. giving no discount). Likewise you're still able to manually attach the promotion to the order, but without any effect.

If your use case requires different discount effect for different intervals of conditions you can add an override. This allows you to define different Activation Requirements with different effects tied to them. In case you do, note that only the rightmost fulfilled override tab will apply its effects on the order.

Combinable promotions

You can set your promotions to be combinable with other promotions. This is useful if you for example want an order to get both the effects from a permanent customer discount and a coupon that the customer brings into your store.

When multiple combinable promotions are applied to an order, all the promotions apply as if they were discounted from the order base price. I.e. if you have an order of $100, and two promotions giving $5 off and 20% off, respectively, the discount amount would be $100 - $5 - ($100*0.2) = $75.