You cannot post to a page.
Pages are static: they don't change, don't have dates (usually), and cannot be tagged or categorized.
Posts can be tagged or categorized, and they have dates.
Posts are displayed in reverse chronological order on the one dynamic page you have for your blog—it changes every time you add a post.
Because posts can be categorized, you can link to their categories. You can use those links in a custom menu, and it will appear that you have different pages for different topics on your site.
Here are details: