Help in config of AWS API Gateway/SQS

I need help in configuring AWS API Gateway and AWS SQS. What we want to do is to send a message to the API gateway. This message should be stored on SQS, but we get right now IAM related errors. Additionally, we want a Lambda function getting the message from the SQS and then sending it as a response back (reply) to the original sender. Means we need also a simple YAML for this request. The goal is to have it gateway/SQS configured and documented via some screenshots on what needs to be done to get this configuration for a simple hello world example ..