You cannot post to a page. On a blog you have only one dynamically changing page: each time you make a post, your blog-page changes.
Posts and pages are very different from each other.
Posts are shown in reverse chronological order, newest at the top, older posts below. Posts have dates (which are part of the link to each post here on WordPress.com). Posts can be categorized and/or tagged. They are a log or journal of your activities, thoughts, or interests. Your dynamic blog-page has a lot of search engine optimization because you are adding new posts and categories all the time.
Pages are static. You write information on a page, and that's it. No dates, no categories/tags. For example, you could have a biography or about page. Or have a page like a lexicon or dictionary of terms you use for the subject you write on. Or an index. They do not have much SEO because they stay the same. Yes, you can continue adding to pages, but soon they will be miles long and it will become difficult to find information.
The magic happens when you use a custom menu. The categories (or tags) you apply to each post are links you can use in a custom menu. Want to write about sports and sermons? Make posts about those topics and use the categories "sports" and "sermons." When a reader clicks on the "sports" category, he or she will see all of your posts about sports. You can use those category links in a custom menu: it will appear as if you are posting to different pages but in fact you are just efficiently organizing your blog so readers can find topics of interest.
If you want all of your current posts (which are now on your "reflections" tab of your top navigation menu) to be separated from newer posts you make in future, bulk edit them to add a category like "old posts."
Here is information about the topics I touched on above: