Welcome, Mahesh! Glad you could join us. :D You've come to the right place to learn about Atheism in an informal way. You might start with the Forum IS EVERYBODY 100% POSITIVE THERE IS NO GOD?. Many groups have their own take on secular lifestyle, from No Nonsense to Wonderism, from big official American Humanist Association to just starting Apostate Atheists.

Please consider joining a group to meet people and talk about anything that's on your mind, Hang With Friends.

I also recommend Eco-Logical and Climate Concerns, since the climate is changing so drastically.

After you've searched for topics of interest in "Groups" above and in the "Forums", don't forget to look at recent activity which hides along the right margin of the page all the way at the bottom. There are many places you can ask questions. If you begin a new discussion with your question, answers will pop up in your latest activity on your profile page. If you ask something in comments, you have to return to that comment wall to see if anyone answered.

Hello Mahesh Kalindu
Welcome to this world of rationality, truth and peace, where common sense and science lead to freethinking wisdom as you will know if you are an atheist.

We invite you to join the busy group "ORIGINS: Universe, Astronomy, Life, Earth, Humans, Religion, Gods, Atheism, Evolution, Darwin..." with 700 discussion topics and 3600 members.
http://www.atheistnexus.org/group/originsuniverselifehumankindanddarwin
Terry