The front page of the blog by default will display your posts (not pages) http://en.support.wordpress.com/post-vs-page/ in reverse chronological order, with the most recently published post on top. If you do not want all the posts to show on the front page, then you can create a static front page “Welcome” for your site and a “Blog” page for posts.
Choice 1 static front page
Choice 2 running page for all posts on front page
Which do you choose? It’s one or the other.
If you choose a static front page then you have to create two pages as I said above. After you do that you go to > Settings > Reading and make the designation change and click “save changes”.