SaaS Appflow Connector to Salesforce in Nodejs

We want to create a case in Customer's Salesforce from our SaaS app. Instead of creating a salesforce client directly in our SaaS app, we thought we can integrate AppFlow so we can manage other "connections" We are thinking about creating an Amazon AppFlow Connector for our SaaS app. Our SaaS app uses nodejs serverless DynamoDB. But I cannot find nodejs connector sdk, nor can I find any instructions on how can have a flow be triggered with source being Rest API or Dynamodb. How are SaaS apps creating a case in Salesforce from using Amazon AppFlow?