Request - Response mock service

I am new soapUI user and i want to use it inorder to simulate responses to specific requests.
in other words, i want to send specific request and get a specific response and incase the request is empty or didn't match any request i want to return an error.

Till now i am able to send requests and when running it i am getting the response in sequence which means every time i press on the play in the request i got the response in sequence
please help
thanks