When you create a new page here -> Write -> Page
You can give the new page whatever title you like and then publish it. Then, provided you have placed the Pages widget in your sidebar a link to that new page will appear in your sidebar.
Do understand though that only one page, usually your front page, will automatically update with the new posts you publish going to the top of the order. The other pages you create sit outside the blog structure and they do not automatically update because they are for static content that rarely, if ever changes. Pages cannot be assigned categories and they do not get the same Google juice that the post on your front page do.