Authorization
To enable SendinBlue subscription service you have to follow next instruction.
- Add your API key

- To find your API key click on your account name in top right corner and choose SMTP & API in dropdown menu. Copy your API key

- Insert your API key in the PopUp plugin settings window and choose a list for subscribe

Custom fields
Also you can add Custom fields which will be shown in your pop up. To do it follow the next steps:
- From the dashboard of your campaigns go to Settings on the left side menu.
- Find Contact Attributes & CRM and click on Configure button.
- To create new custom field click Add new attribute button

- Type a name for your new field and choose its type

- Copy attribute name of your custom field from the list of existing attributes

- Go to PopUp plugin setting window and open Subscribe tab of that pop up where you want to add Custom field. Click on Add button

- In the Name field insert attribute name you’ve copied in step 4

- Add label for this field, click ‘OK’ and save changes.