The four latest articles from the blog category are displayed in a column on your homepage. Then there are links to the 4 next oldest articles. You can change these numbers by editing the content options settings on your site administrator's Blog tab. In the top menu there is a link to your site administrator.
If you want your blog post to be divided into two parts, an introduction and then a separate full-length page, use the Read More button to insert a break.
On the whole page you can see both the introductory content and the rest of the article. You can change the settings to hide the introduction if you want.