**Behavioral Data Hub > Live Aggregates > Create aggregate**.
2. As the aggregate type, select **Profile**.
2. Enter the name of the aggregate.
3. Click **Analyze profiles by** and select **Sum**.
4. From the **Choose event** dropdown list, select the **transaction.charge** event.
5. As the event parameter, select **$revenue**.
6. Set the period from which the aggregate will analyze results to **Lifetime**.
7. Save the aggregate.
**Decision Hub > Segmentations > New Segmentation**.
2. Enter the name of the segmentation.
3. Choose **Add condition** and find the [aggregate counting the sum of all user transactions](/use-cases/referral-program#create-an-aggregate-that-counts-the-sum-of-all-user-transactions), created in the previous step.
4. From the **Choose operator** dropdown, choose **Number**, and then select **More or equal to**.
5. In the next field, enter the required transaction value, in our case it is `20`.
6. Choose **Add condition** and find **phoneVerified** tag.
7. From the **Choose operator** dropdown, choose **Is true**.
8. Choose **Add condition** and find **webhook.response** event.
9. Click the + where button, from the **Choose parameter** dropdown menu, choose **name**.
10. From the **Choose operator** dropdown, choose **Contain**.
11. In the next field, type `add points to user 1`.
**Behavioral Data Hub > Expressions > New expression**.
2. Enter the name of the expression.
3. Leave the **Expression** option at default (**Attribute**).
4. Click the **Select** button.
5. Choose **# Constant**.
6. Open the settings of Constant value by clicking `0`.
7. In the field below, type `500`
8. Click **Save**.
## Create an expression to determine the maximum number of points to be awarded
---
In this part of the process, you will create an expression that determines the maximum number of points that can be awarded to **user 1**. In our case, it is 1500 points. This expression will be used to [calculate the number of points remaining for user 1](/use-cases/referral-program#create-an-expression-that-calculates-the-number-of-points-remaining-for-user-1).
1. Go to **Behavioral Data Hub > Expressions > New expression**.
2. Enter the name of the expression.
3. Leave the **Expression** option at default (**Attribute**).
4. Click the **Select** button.
5. Choose **# Constant**.
6. Open the settings of Constant value by clicking `0`.
7. In the field below, type `1500`
8. Click **Save**.
## Create a workflow that generates a unique referral code
---
In this part of the process, you will create a workflow that will generate a unique referral code for both new users who are about to join the application and existing ones, which will be stored in the **my_referral_code** attribute. In addition, you will generate a special attribute that will be used to count the number of codes granted to **user 1** - **referral_points_received**.
1. Go to 
**Automation Hub > Workflows > New workflow**.
2. Enter the name of the workflow.
### Define the trigger nodes
Configure the conditions that will trigger the workflow. In this case, you will run a workflow for new users who are just joining the application and for existing users for whom the code has not been generated yet.
#### Define the Profile Event node
1. As the first node of the workflow, add **Profile Event**. In the configuration of the node:
1. From **Choose event** dropdown menu, choose `client.add` event.
2. Confirm by clicking **Apply**.
#### Define the Audience node
1. Add the **Audience node**.
2. In the configuration of the node, leave the value of the **Run trigger** option at default (**one time**).
3. In **Define audience**, choose **New Audience** and click **Define conditions**.
1. As the first condition, from **Choose filter** dropdown menu, choose `anonymous_type` attribute.
2. From the **Choose operator** dropdown list, select **Equal**.
3. **Result**: A text field appears.
4. In the text field type `NONE`.
**Automation Hub > Workflows > New workflow**.
2. Enter the name of the workflow.
### Define the trigger nodes
Configure the conditions that will trigger the workflow. In this case, the workflow is triggered for invited users who have already verified their phone number or completed a transaction. Meeting both conditions will also be checked in a further step of the workflow.
#### Define the Profile Event node
1. As the first node of the workflow, add **Profile Event**. In the configuration of the node:
1. From **Choose event** dropdown menu, choose `transaction.charge` event.
2. Confirm by clicking **Apply**.
#### Define the Profile Event node
1. Add **Profile Event**. In the configuration of the node:
1. From **Choose event** dropdown menu, choose `client.addTag` event.
2. Click the + where button, from the **Choose parameter** dropdown menu, choose **name**.
3. From the **Choose operator** dropdown, choose **Equal**.
4. In the next field, type `phoneVerified`.
{
"time": "",
"label": "refer a friend points",
"action": "points.upcharge",
"client": {
"id": {{event.params['body.customers[0].id']}}
},
"params": {
"points": {% expression %} f05e644c-7009-49d0-9208-18e9319af4a5 {% endexpression %},
"description": "referral_points"
}
}
**Behavioral Data Hub > Expressions > New expression**.
2. Enter the name of the expression.
3. Leave the **Expression** option at default (**Attribute**).
4. In the formula of the expression:
1. Click **Select**.
2. From the dropdown list, select **Function > Profile**.
3. Click the **unnamed** node.
4. At the bottom of the page, click **Choose attribute**.
5. From the dropdown list, select the [expression with the maximum number of points](/use-cases/referral-program#create-an-expression-to-determine-the-maximum-number-of-points-to-be-awarded) you created earlier.
6. Click + button and from the dropdown list select **Profile**.
7. Click the **unnamed** node.
8. At the bottom of the page, click **Choose attribute**.
9. From the dropdown list, select the **points.upcharge** attribute.
10. Click the + button and change it to `-`.
11. In the upper-right corner, click **Save**.
12. In the upper-right corner, click **Publish**.
{ "notification": { "title": "You have earned 500 points!", "body": "Congratulations!!! You just earned 500 points for the registration of a new referred user!", "sound": "default", "priority":"high" }, "data": { "issuer": "Synerise", "message-type": "static-content", "content-type": "simple-push", "content": { "notification": { "action": { "type": "OPEN_APP" } } }, "payload": { "type": "points-earned", "pointsReward": "{% expression %} f05e644c-7009-49d0-9208-18e9319af4a5 {% endexpression %}", "title": "You have earned 500 points!", "subtitle": "Thank you for being with us!", "description": "You receive 500 points for the registration of a new user. You can earn {% expression %} 819f23f5-4f97-4039-b3ef-eb83130ac7c6 {% endexpression %} more points for the registration of additional users in the application." } } }