Hi, I am new to linux. pls let know how to post questions. thanks.
Welcome to the Linux open source world! 
You just posted a question without knowing it. The ‘thread’ you posted was a question. Before posting any more help questions, however, you need to know that questions need to be posted in the correct places; like questions on installing Linux need to be in the Install/Boot/Login section and if you want answers to questions on hardware, the Hardware section is the place to post questions, and so on.
Also, it’s a very good idea to read the stickies at the top of the forum concerning your question first - many of them have already been answered in there.
Try searching google, and try searching the forum, then if you come up blank, or don’t understand something, ask away…
(the general protocol being ask in the same thread if it’s directly related, and isn’t ages old. If it’s a new question, or the thread is very old, start a new one.)