If you are going to create a blog, as opposed to a website you will probably mostly use posts and may not have much need for pages or even menus.
Posts
The Classic blog consists of a series of entries arranged in reverse chronological order. You make a new post and it goes to the top of your home page, pushing previous entries down. This is a post.
Pages
Pages are a special type of post that stand outside the time line and can be hierarchical (posts can have parents).
You will need to link to the pages, perhaps in a menu, for visitors to find them.
This site consists mainly of pages. These are linked to from the left hand navigation sidebar (unless on mobile where they are converted to a drop down menu).
If you are making a School website you may want to use pages for providing the bulk of the information and posts for news.
The reverse ordered posts do not need to appear on the home page. You can set your sites home page to be a static pge and have a separate page that will display post. This site uses the Posts page for that.
