Hi @salamiadil,

You can certainly send emails after a placed order event. You should have two flows in our Flow Library which you can find in your account specific to BigCommerce that you should be able to find which are titled Shipping Confirmation and Order Confirmation. Flow Library

This article on our Guide to Using Flows to Send Transactional Emails is a good read to understand what Klaviyo classifies as a transactional message and the steps you’ll need to take if you’d like an email to be marked as transactional since these emails will be sent to those customers who may have unsubscribed from marketing emails. 

Based on this content piece, Getting Started Handbook - Guide to Creating a Post Purchase Flow Shipstation is mentioned if you’d like to send a communication with regards to sending instructions to your customers if this is something your products require.

Once you take a look through those articles, it should provide the information and starting points you’ll need to start the process of getting these messages sent to your customers. If you do elect to send your transactional emails out of Klaviyo, I would also make sure that if these messages are already being sent from a different platform to disable those communications before you set them live in Klaviyo so customers are not receiving double communication.