Klaviyo integration
Go to 'Settings -> Integrations'. Select Klaviyo from the list of integrations.
Click the "Connect to service' button. This will open Klaviyo. Enter your credentials to login to Klaviyo. You then have to permit MakePlans to connect to your Klaviyo accout.
You will then return to MakePlans to select which MakePlans account to connect to. Select your account.
As a final step you will have to select which list in Klaviyo you want MakePlans to add new subscribers to. Click on a list and you will see "This service is connected." next to it.
That's it. MakePlans will now automatically add a new subscriber in your Klaviyo list whenever a new booking is made.