Kumar,
I think you need to spend sometime reading the documentation on the testng site. Most of your questions would be answered on your own once you read the documentation.
When you right click your class and run it as run as TestNG test, what TestNG does is, it adds up your @Test annotated test methods into a <test> tag which again gets wrapped up into a <suite>.
In short a test suite <suite> contains of one or more <test> tests. Every <test> contains one or more @Test annotated test methods.
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Thanks & Regards
Krishnan Mahadevan
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