Smart Conversations is currently in beta and is available to select customers only. Contact Sinch or your Sinch Account Manager to request early access.
Once you have signed up as a beta customer, then it is straight forward to configure some of the features and setup the webhook on the Sinch Customer Dashboard.
Go to any of Conversation API "app" that you have setup with channels, go to the bottom of the page. Press "EDIT" then toggle "Enable Smart Conversations". Now you can select the feature/s to turn on.
It's possible to enable Sentiment Analysis and Natural Language Understanding to start testing right away. With other Smart Conversations' features, Sinch will need to customize based on your business requirements. Your Sinch Account Manager will help you with that.