How to become a WhatsApp Beta tester?

So many people using WhatsApp messenger. And many people like new WhatsApp features getting early in the official release, that called Beta tester

What is a beta program? 

WhatsApp has invited you to a testing program for an unreleased version of the WhatsApp Messenger app. As a tester, you'll receive an update that includes a testing version of the WhatsApp Messenger app, which may also include unreleased versions of its instant app.

How to you become a WhatsApp Beta tester?

Before some months we are getting the Beta version directly from play store. But now if you, not a Beta tester. Then you couldn't come to the Beta tester directly from play store. If you try on the play store you can see the result like this. ”Beta programme is full” then how can come in a Beta tester.?

(click here and go to the Beta tester site)
So open your chrome browser and search ”WhatsApp Beta tester” now you can see this screenshot below.

Click on the button ”BECOME A TESTER” now you are a Beta tester.
Now restart your phone and open play store and check the Beta list.