# Principia

> Connect Principia to your Cademí: the product SKU and the authorization token in a one-time sale delivery, the beta notice and the Postback URL.

Connect Principia to your Cademí so each approved purchase gives the student access on its own. You need the product SKU, the authorization token of your Principia account and a postback pointing to Cademí.

## 1. Create the delivery in Cademí

1. In the Cademí dashboard, open **Sales > Deliveries** and add a delivery.
2. In **Select a Gateway**, pick **Principia**. The screen shows the notice **This gateway is in the beta implementation phase, but you can already use it**: carry on as usual.
3. In **Delivery Name**, enter a name that helps you recognize it later.
4. **Sales Mode** shows only **One-time sale**: a Principia delivery does not have the **Subscription** option.
5. The **Gateway connection** section shows the **Product SKU** and **Authorization Token** fields and the **Postback URL**.

Keep the delivery open: you come back to it in the next steps.

## 2. Find the product SKU

1. In your Principia account, copy the SKU of the product you deliver through Cademí.
2. Paste the SKU into **Product SKU** in the Cademí delivery.

## 3. Copy the authorization token

If you already registered your Principia token in another delivery, pick it in **Use an already registered token** and go to step 4.

1. In your Principia account, copy the authorization token.
2. Paste the token into **Authorization Token** in the Cademí delivery.

## 4. Set up the postback

The postback address is set up in your Principia account: paste the **Postback URL** of the delivery there and save. Then, in Cademí, save the delivery.