Dear MRKUMAR Ji,
The process is the same as you have posted your intro above.
If you click on the 'FORUM' on the lefet in the top bar above, it will take you to a page with all the sub forums here (like General Discussions, etc.).
Click on any of them, you will enter these sub forums and will see various topics (threads). You can post a reply on any of them (there is a 'Reply to Thread' button you can click on the bottom left (before the page #), or you can post by writing and posting from the 'Quick Reply' box below the page #.
Of course under each sub forum topic, you have the option to create a new topic (thread), that interests you and post that. However make sure that you read the description for each forum that is provided - and based on your topic, select the one that fits closest to your topic. There are restrictions on what you can post in a couple of sub forums.
Hope this helps.
Welcome to all the new comers.
Regards,
KRS
(Forum Moderator)