Automaticity of next step in this site?

According to the rules,

1 - 30 posts or less than 14 days membership: You can start a thread only in the Newbie Forum.
31 - 300 posts or less than 28 days membership: You can start a thread in the Newbie Forum and everywhere else except for the Main Member Forum.
300+ posts and greater than 28 days membership: You become a Senior Member, and can start a thread anywhere including the Main Member Forum.

How do I know when i am ready to post elsewhere (but the Main member Forum)? Is it automatic or I have to request my graduation? :-)

It’s automatic.

Well your amount of posts is on the left side, bottom of the box of your first post on this page. 45 posts so far for you. You joined on January 8th, 2005. To find this information left click on your name “Mexmuscle” then click on “view public profile”. Hope that helps.