1. Start by selecting the 'Retargeting' tab.
2. Next, choose to either create a new audience or select an existing one.
3. Then, click to create a custom audience.
4. Choose 'Customer list' as your audience source.
5. Move forward by clicking 'Next'.
6. Choose how to add customers: by CSV upload or using smart lists.
7. If uploading, click 'CSV upload'.
8. Now, add a name for your audience.
9. Provide a description for your audience.
10. Select the 'Smart List' option to proceed with existing lists.
11. From the dropdown, pick your preferred smart lists.
12. Enter a unique name in the provided field for this audience.
13. Add a clear, brief description.
14. Lastly, click "Create Audience"
