As soon as DIDforSale gets access to <didML> document, phone system will convert the text to audio and play the messages to the caller. Once the message is played it will forward the call to another number as specified in the instructions.
Please Note: Only one document can be served at one time, but you can link other documents based on input from the user. This way you can build a complex voice application. Like if Press 1 to do this, or Press 2 to do that else hangup.