Once installed the plugin is quite easy to use.
Go to Window -> Show View -> Other -> Unit Test Quality Analyser

You can then select the test method you want to be analysed and click on the 'Test Quality Analysis' button

The rating will be then displayed. In this case it is 0/3.
The score is provided for the following criteria
1.for javadoc comments
2.for the number of asserts
3.for the precision of the asserts, i.e if a field is modified in the method being tested, is an assert present for it
The 3rd on has not been developed yet and is currently in progress.