Once installed from the chrome webstore, you will be able to create a monitoring on a Google Apps mail box. First you will have to validate authorization required, check video below to see whole setup process.
Once you buy a license you will be able to run monitoring for 30 days !
5 minutes is enough to run a test and check audit on a mail box.
This time is also to limit usage of free version to not allow easy monitoring for free. Audit monitoring is made for legal reason !
To buy license just click on the button in the interface :