Lets start with the last post you have created for your blog.

1. Go ahead and sign into your site, then go to the most current blog post.

2. Click on edit post on your task bar on top of the site

Now you are in the edit mode of your last post.

3. Read down your blog and figure out where you would like to put the more button, or in other words, how much of the post do you want to show on your blog page.

On mine below I decided to put the more button after the third paragraph