The integration is very simple. You can either follow the steps below or use our step-by-step guide:
https://www.biberei.de/how-to-integrate-mailerlite-into-your-bubble-io-application/

1. Install the plug-in

2. Add the API key in the plug-in field (this can be found within the settings section --> integrations --> Developer API of your mailerlite account.

3. To show all subscribers or all groups, just create a repeating group and use the external data API to show your data

4. To show all subscribers within a group, you need to create another input field (e.g. dropdown) where you can select the groups for which you want to show the subscribers. The ID of this group acts as an input parameter to search for this group.

5. To add a new subscriber, the email field is mandatory.

6. To add a new subscriber to a specific group, the group ID must be given as an input parameter. You can either paste the ID or look for a group first based on a name. Either way you prefer - you need to pass the exact ID or the exact name.

We also created a step-by step tutorial which includes many pictures:  https://www.biberei.de/how-to-integrate-mailerlite-into-your-bubble-io-application/