You need to take your question to the 'Beginners Corner' forum.
You will also need to provide more information.
What JBoss version?
What steps have you performed to deploy the datasource?
Are there any errors when you deploy the datasource?
Have you checked 'JNDI View' in the JMX console to see if the datasource is bound?
How are you trying to obtain the datasource?
Where are you trying to do this? From a component running the in the app server or is it a remote client?
Also do not try and explain exceptions just post the exception with its stack trace and message.